Biodiversity of the Rewa Head B Zoological Society of London ...

Zoological Society of London, Regents Park, London NW1 4RY 

www.zsl.org 

Registered Charity no. 208728 

Biodiversity of the Rewa Head B

ZSL Conservation Report No.10 

A Biodiversity Assessment 

of the Rewa Head, Guyana 

July 2009 

Rob Pickles 

Niall McCann 

Ashley Holland

Published by: The Zoological Society of London, Regents Park, London, NW1 4RY 

Copyright: © Zoological Society of London and contributors 2009. 

All rights reserved. The use and reproduction of any part of this 

publication is welcomed for non-commercial purposes only, 

provided that the source is acknowledged. 

ISSN: 1744-3997 

Citation: R. Pickles, N. McCann, A. Holland (2009) 

A Biodiversity Assessment of the Rewa Head, Guyana. 

ZSL Conservation Report No. 10. The Zoological Society of London, 

London. 

Key Words: Guyana, Rewa, biodiversity, threatened species, conservation, giant 

otter, logging, mining, ecosystem services 

Front cover: Jaguar photographed in the Rewa Head © Gordon Duncan 2004 

Page layout: candice@chitolie.com 

The Zoological Society of London (ZSL), founded in 1826, is a world-renowned 

centre of excellence for conservation science and applied conservation (registered 

charity in England and Wales number 2087282). Our mission is to promote and 

achieve the worldwide conservation of animals and their habitats. This is realised 

by carrying out field conservation and research in over 80 countries across the 

globe and through education and awareness at our two zoos, ZSL London Zoo and 

ZSL Whipsnade Zoo, inspiring people to take conservation action. 

The aim of this Conservation Report series is to inform people of the work that 

ZSL and its partners do in field conservation. Results of work carried out in field projects 

are often only reported in unpublished technical reports. This series seeks to bring 

this grey literature into a more accessible form to help guide conservation 

management and inform policy. The main intention is to report on particular 

achievements, especially where lessons learnt form the field can benefit other 

conservation professionals. The results of field surveys will also be disseminated 

through this series. 

The primary audience for these reports is ZSL’s conservation partners. These 

include government departments, private sector actors and conservation 

organisations. In some cases this type of report will also be useful for local 

communities. This series will be published in English and other languages as 

appropriate. Because only a limited number of hard copies will be produced, 

electronic versions of all these reports will be available through the ZSL library. 

(https://library.zsl.org)

A Biodiversity Assessment 

of the Rewa Head, Guyana 

July 2009 

R.S.A. Pickles 

N.P. McCann 

A.P. Holland

Co n t e n t s 

Executive Summary 3 

Acknowledgements 4 

Team 5 

Introduction 6 

Background to the expedition 6 

The Guianan Shield 6 

Situation of the Rewa Head 7 

Human occupancy and visits above Corona Falls 8 

The Expedition 10 

Chapter 1. Mammal Species Diversity and Relative Abundance 11 

Flagship Species: The Giant Otter 11 

Camera Trapping Survey 13 

Observations 17 

Chapter 2. Bird Species Diversity and Relative Abundance 20 

Mist Netting Survey 20 

Drift Spot Count Survey 22 

Chapter 3. Reptile Species Diversity 24 

Chapter 4. The Future State of the Rewa Head: 

Identification of Stakeholders 26 

Chapter 5. Conservation 31 

Conservation Recommendations 32 

References 34 

Appendix 1. Mammalian Diversity 37 

Appendix 2. Avian Diversity and Relative Abundance 39 

Appendix 3. Reptilian Diversity 47 

Appendix 4. EPA permission to conduct biodiversity research 48 

Biodiversity of the Rewa Head 1

Figure 1. Jaguar (Panthera onca) Photograph taken by Gordan Duncan in 2004. During that six 

week trip the water level was exceptionally low and 10 jaguar were observed. 

Figure 2. Goliath bird-eating spider (Theraphosa blondii), one of the giants of Guyana’s interior. 

Gordon Duncan. 

2 Biodiversity of the Rewa Head

ex e C u t i v e su m m a r y 

The reason for the expedition 

This report lays out the findings of a six week expedition above Corona Falls to 

the split between the East and West River Rewa in Guyana’s Upper Takutu-Upper 

Essequibo Region, documenting the fauna observed along 60 river miles. The Rewa 

flows between the Conservation International Upper Essequibo Concession and 

the proposed Kanuku Mountains Protected Area, feeding the biologically important 

Rupununi Basin. Yet despite the Rewa Head appearing to be preserved in a pristine 

state it has not been explored scientifically to assess its conservation value. The 

initial focus of the expedition was the endangered giant otter (Pteronura brasiliensis), 

but alongside the giant otter research we set up a line of camera traps and mist-net 

stations as well as conducting drift surveys to record the riparian and forest fauna. 

Major Findings 

A line of camera traps positioned in the 25 miles immediately above Corona Falls 

recorded a total of 17 mammal species, including puma (Puma concolor), margay 

(Leopardus wiediii), giant anteater (Myrmecophaga tridactyla) and Brazilian tapir 

(Tapirus terrestris). In total, 33 mammal species were recorded during the course 

of the expedition including all 8 of Guyana’s monkey species. Mist netting and 

drift spot counts yielded a total of 187 bird species from 47 families. With the 

inclusion of Smithsonian Institution data from 2006, the species list for the Rewa 

Head rises to 251. These include 10 Guianan Shield endemics, two species of which 

had particularly small ranges: Todd’s antwren (Herpsilochmus stictocephalus) and 

the little hermit (Phaethornis longuemareus); as well as the rare and charismatic 

harpy eagle (Harpia harpyja) and crested eagle (Morphnus guianensis). We also saw 

evidence of the threatened bush dog (Speothos venaticus), yellow-footed tortoise 

(Geochelone denticulata) and giant armadillo (Priodontes maximus). In total, 50% 

of Guyana’s threatened species were observed above or immediately below Corona 

Falls. Goliath bird-eating spider (Theraphosa blondii) was recorded in the Rewa Head 

and of particular note, 5 green anacondas (Eunectes murinus) over 15ft long were 

encountered. One individual measured was found to be 18’2”. Wildlife, particularly 

game species, was found to be naïve, with tapir, paca and black curassow allowing 

us to approach within several metres without fleeing. 

Birds: 251 species 

Mammals: 33 species 

Threatened fauna: 14 species 

Conservation Recommendations 

The results of this brief survey reveal the Rewa Head to be biologically rich and an 

important region for threatened lowland rainforest and riparian fauna. It is also the 

headwater of an important tributary feeding the Essequibo. The Rewa Head is currently 

under no protection and although the government has recently outlawed small-scale 

gold mining from the river, the area does constitute a logging concession which 

may well be developed in the coming years. Due to the ease with which charismatic 

rainforest fauna such as tapir, anaconda and harpy eagle can be seen; there is the 

potential for developing a modest, regulated tourist industry with the villages of 

Rewa and Yupukari. The infrastructure already in place in these villages could play an 

important role in establishing programmes of scientific investigation in the area for 

exploring the biodiversity of the Guianan Shield ecoregion as well as the distribution 

and biology of endangered species. 


aC k n o w l e d g e m e n t s 

Many thanks go to Diane McTurk for help and advice, allowing us to stay in Karanambu 

while analysing our data and collecting samples from her Rupununi otters. Thanks 

to Margaret Chan-a-sue for logistical support in Georgetown and to Peter Taylor 

for sound advice, tireless energy and for pointing us in the right direction. We are 

extremely grateful to Graham Watkins for criticism and advice and to Nicole Duplaix, 

for introducing us to the Rewa to begin with. This expedition was funded through 

generous grants from the Linnaean Society’s Percy Sladen Memorial Foundation, ZSL’s 

Daisy Balogh Travel Award and through NERC expedition funds. The majority of the 

expedition costs were self-financed. 


te a m 

Rob Pickles. BSc Zoology 

Rob and Niall first worked together on giant otters in a Royal Geographical Society 

funded expedition to Bolivia in 2003. Following on from this in 2006 Rob began a 

PhD investigating the population genetics of the giant otter at the Institute of Zoology, 

Zoological Society of London (ZSL) and the Durrell Institute of Conservation and 

Ecology (DICE) at the University of Kent. He is now in his third year of study. 

Niall McCann. BSc Zoology 

After finishing his degree in zoology at Bristol University, Niall worked as a research 

assistant on ZSL’s jackal project in Namibia and is about to embark on a PhD studying the 

population connectivity of Baird’s tapir in Honduras based at the University of Cardiff. 

Ashley Holland 

Ash has worked with both the Smithsonian Institute and the BBC and was the local expert 

and naturalist as well as providing the logistical support to get up to the survey area. 

He has explored the Rewa Head on several occasions and worked with Conservation 

International during their Rapid Assessment Programme to the Eastern Kanukus after 

working at Karanambu Ranch for many years and is currently the manager of the black 

caiman research project in Yupukari. 

Kevin Alvin 

Kevin is a resident of Katoka village and knows the river well, working with the 

Smithsonian Institution mist netting and with the BBC in the filming of ‘Lost land of the 

Jaguar’ and ‘Planet Earth’ series. He has worked with Ash for over five years. 

Ryol Merriman 

Ryol is a resident of Yupukari and has been working with Ash for over 10 years and has 

visited the Rewa Head on several occasions, working with the Smithsonian and BBC. 

Fernando Li 

Nando is the manager of the black caiman project at Yupukari, funded by the Rupununi 

Learners Foundation. It is a long-term ecological study looking at the ecological role 

the species plays as well as sustainable resource use by local villages. 

Doris Merriman 

Doris was the expedition cook 

Figure 3. Ryol and Doris Merriman and bowman ‘Nando Li. 


in t r o d u C t i o n 

Background to the expedition 

The expedition was initially conceived as a sampling trip to collect faecal samples from 

the giant otter (Pteronura brasiliensis) to obtain DNA for use in a phylogeographical 

study being carried out by Rob Pickles at the Zoological Society of London and the 

University of Kent. The Rewa Head was purported to have evaded the depredations of 

hunters during the trade in giant otter fur and due to its isolated nature has witnessed 

little human impact over the centuries. It was recommended by Nicole Duplaix who 

conducted the first study on giant otters in the 1970s in Suriname. Due to the unexplored 

and unprotected status of the Rewa Head, it was decided to maximize the time spent 

above Corona Falls by conducting coincidental biodiversity studies, namely camera 

trapping, mist-netting and spot-count transects. 

The Guianan Shield 

Figure 4. The Guianan Shield straddles five countries in northern South America and its streams feed 

three drainage basins. High degrees of endemism and species diversity coupled with the largest tract 

of unbroken tropical forest anywhere in the world makes this an extremely important eco-region. 

Guyana is located in the northern part of the Guianan Shield, a vast Precambrian craton 

uplifted during the formation of the Andes in the Oligocene, 3.5 million years ago. The 

craton formation has determined the hydrology of the region, resulting in a watershed 

across its back which splits the flow of streams north-south. Across this 250 million 

hectares of northern South America lies the largest tract of pristine forest anywhere in 

the tropics. The Guianan Shield contains some of the most carbon-rich forests in South 

America and represents an important carbon dioxide sink in the fight against climate 

change (Saatchi et al 2007). Added to this, the Shield possesses extremely high levels 

of biodiversity and endemism as a result of Pleistocene refugia. Over 20,000 species of 

vascular plants are found in the Guiana Shield, 35% of which are endemic. Similarly 975 

bird species are found in this eco region, of which 15% are endemic (Ellenbroek 1996). 

Lying between 1 and 9 degrees north of the Equator with a coast in the Carribean, 

Guyana receives most of its weather patterns from the Caribbean Intertropical 

Convergence Zone (ICZ) with a seasonality driven by a rainy season arriving in early 

May lasting until mid-August, followed by another short rainy season in December. Its 

forests are hot and humid with between 2000-4000mm of rain annually. 


Unlike its larger neighbour to the south, Guyana has never had government-led drives to open 

up the interior of the country and so the forests have remained largely intact. While at 215,000 

km 2 it is similar in land mass to Great Britain, its population is only 870,000 strong with a 

population density of 3.5 per km 2 , 90% of whom live in a strip of land around the industrialised 

northern cities of Georgetown, Bartica and Linden. Land cover remains 76% rainforest and 

while some cattle ranching occurs in the natural Rupununi savannahs and small-scale gardens 

are cultivated by Amerindian communities, there is very little agriculture in the interior. 

Situation of the Rewa Head 

Figure 5. Location of the Rewa Head and extent surveyed by this expedition. 


The Rewa Head is located in Southern Guyana, in Upper Takutu-Upper Essequibo 

Administrative Region. It takes its water from tributaries feeding from the Kanuku 

Mountains in the South and drains north into the Rupununi and Essequibo before 

flowing into the Atlantic. The Rewa is termed a ‘blackwater river’ due to the humic, yet 

relatively sediment-free waters. Following the Rewa upstream from where it is met by 

the Kwitaro, the lowland rainforest vegetation type continues up above Corona Falls. 

Above here the river is fractured by a series of cataracts and falls which prevent the 

colonisation of the headwaters by fish common in the Lower Rewa, such as arapaima 

(Arapaima gigas), lukanani (Cichla ocellaris) and arawana (Osteoglossum bicirrhosum). 

Likewise the black caiman (Melanosuchus niger), spectacled caiman (Caiman yacare) 

and giant Amazonian river turtle (Podocnemis expansa) are not found above Corona 

Falls. Above the falls the only fish species of human value are haimara (Hoplias aimara) 

and black piranhas (Serrasalmus rhombeus). A series of narrow tributaries flow into 

the Rewa along its meandering path above the falls. Some, such as Louis Creek and 

Kubrar Creek, can be followed for 6 miles or so, before fallen trunks block passage. 

Some of the names of the creeks, camps and falls used here are old and date back to 

the balatta bleeders, though most are names given by Ashley Holland and his guides 

from previous trips. Continuing upstream, the river narrows to 20ft wide by N2° 45.358’ 

W58° 37.415’ and shortly after, at N2° 45’ W58° 33’ the vegetation becomes scrubby 

riparian bush with dense bamboo groves, cecropia and guava, continuing with patchy 

forest to N2° 42’ where dense forest once again predominates. 

Human occupancy and visits above Corona Falls 

The Rewa has historically been inhabited by Amerindians. Evidence can be seen in 

the petroglyphs found on the falls, predominantly Corona, where geometric designs 

along with grooves purported to be for sharpening hand-axes can still be seen. Those 

responsible for the artwork have long since disappeared, leaving the forests above the 

falls empty of people. 

Figure 6. Hand-axe sharpening grooves and geometric designs below Corona Falls on the River 

Rewa testify to the fact that there were once indigenous people inhabiting this area. 


The first outsiders to begin exploitation of the region were the balata bleeders in the 

early 20 th Century, who even ventured up as far as the East-West Split in order to tap 

the low-grade latex from the trees. The bleeders cut paths through the forest which 

are still recorded in the 1970 aerial survey. The petrochemical industry spelled the end 

for the balata industry and the last few bleeders likely ventured above Corona Falls in 

the 1960s. The gold found in the alluvial sand of the Rewa Head has been a lure in the 

past and several small mining operations worked the river above the falls in the early 

1990’s. Low gold prices coupled with the expense and extreme logistical difficulty 

of portaging dredging equipment over the falls led to the eventual abandonment of 

these claims after a few years. The rotting equipment used during the dredging can 

still be found in the forest. 

Figure 7. Old compressor used by dredgers to compress air for the divers to breathe. Abandoned 

and now rotting in the forest. 

Since the last venture there have not yet been any further dredging operations anywhere 

along the Rewa and the forests have never been explored for commercial timber. 

Macushi Amerindians from Rewa Village hold garden plots in the fertile alluvial soil 

of the Lower Rewa and Wapishanan Amerindians from Shea in the shouth savannahs 

travel to the Kwitaro to farm by the river there. The river and the forests here are 

extremely important to the Amerindians and people travel as much as 75 miles from 

their village to work a plot of land or fish and collect turle eggs at certain times of the 

year. However the villagers do not travel above Corona Falls and consequently, since 

the decline of the balata industry and the dredgers above the falls, the wildlife has 

ceased to be exposed to hunting pressure and is allowed to flourish. 

Our expedition in January 2009 followed on from a Conservation International (CI) 

Rapid Assessment Programme in the Eastern Kanuku Mountains and Lower Kwitaro 

River in 2001 and a Smithsonian Institution bird specimen collecting expedition to 

the Rewa, collecting from two sites, one below Corona Falls in the Lower Rewa and 

the other above the falls. In 2007 the BBC carried out an expedition to the Upper 

Essequibo and spent several days above Corona Falls. filming wildlife. Ashley Holland 

has explored the Rewa Head several times with Gordan Duncan. Duane de Freitas has 

also led several trips above the falls for birdwatchers and tourists. 


th e ex p e d i t i o n 

The expedition ran from the 31 st December 2008 to the 31 st January 2009. Niall and 

Rob met with Ash and the rest of the team at Annai on the 31 st and proceeded up the 

Rupununi before heading up the Rewa. The next few days were spent motoring up to 

Corona Falls, the juncture between the Lower Rewa and Rewa Head, arriving there on 

the 3 rd January. The next three days were spent portaging over the string of falls and 

cataracts, before motoring on up to the split between East and West Rewa, setting 

up the camera trap grid as we went. In this way we worked our way up as far up the 

Rewa as was navigationally feasible, before slowly working our way back down the 

river, surveying as we went. We took two 7m heavy duty aluminium boats with 15hp 

outboard engines owned by Ashley Holland and carried 150 gallons of fuel for the trip, 

leaving caches above and below Corona Falls for the return journey. We carried three 

GPS units: two Garmin E-Trex and a Garmin GPSmap 60Cx for work under the canopy. 

General positioning was conducted using Guyana Survey maps printed at the Survey 

Department of Guyana, Georgetown. 

Figure 8. Portaging the boats over a cataract upstream of Bamboo Falls. 

First base was at the East-West Split at N2° 37.752’ W58° 37.152’, from which we 

explored the West branch of the Rewa up to 2°37’ before a series of fallen trees blocked 

passage. Three days were spent at “Split Camp” from the 10 th to the 13 th January. From 

there we travelled downstream to “Tayra Camp” at N2° 45.358’ W58° 37.415’, erecting 

the second netting site, conducting drift transects and searching for sign of giant otter 

until the 16 th . The following camp was at N2° 53.697’ W58° 35.225’, known as “Onca 

Camp”. We remained here until the 19 th , surveying and netting before moving further 

downstream to “Monkey Ladder Camp” at N2° 59.773’ W58° 35.971’. While here we 

explored Louis Creek up to N2° 58.381’ W58° 32.799’. We were severely hampered 

by inclement weather, experiencing two torrential downpours which lasted for 36hrs 

and resulted in the river level rising by 10ft. The final camp above Corona Falls was at 

“Powis Camp”, below Powis Falls at N3° 07.901’ W58° 37.896’. We remained at Powis 

until the 27 th January surveying and netting, before collecting up the string of camera 

traps and portaging our gear back over Bamboo and Corona Falls. The night of the 

27 th we stayed at a campsite below Corona Falls, before departing the following day, 

motoring the next three days back down the Rewa and Rupununi, reaching Karanambu 

on the 31 st of January. In total we spent 22 days above Corona Falls. This report is a 

presentation of the wildlife encountered during that time. 


Chapter 1. Mammalian Species Diversity and Relative Abundance 

The study of mammalian diversity and relative abundance was principally based on a 

line of camera traps erected in the 25 miles of river immediately upstream of Corona 

Falls. The species list presented in the appendix is a combination of observations 

recorded through camera trapping, sightings made while on drift transects and 

opportunistically as well as indirect evidence such as scats, footprints and burrows. 

Our reference was Emmons and Feer (1997) Neotropical Rainforest Mammals however 

we have used the most recent taxonomic revisions including the Guianan red howler 

monkey, (Alouatta macconnelli) and red-backed bearded saki (Chiropotes chiropotes). 

Principal Findings 

• 33 species of mammal recorded including all 8 of Guyana’s primates and 5 

species of felid. 

• Healthy population of endangered giant otter ( Pteronura brasiliensis) with 5 

groups recorded above the falls, equating to one group every 12 miles. Four 

groups were recorded below the falls. 

• 17 species of medium to large mammal recorded in camera traps including 

puma (Puma concolor), giant anteater (Myrmecophaga tridactyla) and margay 

(Leopardus wiedii). 

• Indirect evidence for the presence of bush dog ( Speothos venaticus) and giant 

armadillo (Priodontes maximus). 

• High abundance of Brazilian tapir ( Tapirus terrestris) with 5 encountered on 

the river and approximately 2.5 tapir roads crossing the river every mile. The 

animals encountered appeared naïve, due to the absence of hunting. 

Flagship species: The Giant Otter 

The highly charismatic giant otter (Pteronura brasiliensis) was the main focus of the 

expedition, as we were there to collect faecal samples for genetic analysis. The giant 

otter population is in the process of recovering from a hunting-mediated population 

crash in the last century which drove the species down to an estimated 3000 individuals 

range-wide (Carter & Rosas 1997). While no official estimate of pre-hunting population 

size exists, judging by skin export figures (Carlos et al 1985, Schenck 1996), it could 

easily have been as high as 50,000. Since placing the giant otter in CITES Appendix 

1, the removal of an international market in giant otter skins has seen numbers rise. 

However, it remains under threat particularly through habitat degradation, mercury 

poisoning, and direct conflict with fishermen (Harris et al 2005, Groenendijk et al 2005). 

Throughout the population crash the Guianan Shield remained a stronghold for the 

species, a low human population density coupled with an interior which had yet to be 

opened up led to the giant otter surviving in this region while in other parts of South 

America it suffered local extirpation. 

The work of Diane McTurk and Karanambu Ranch fomented the impression of 

this charismatic predator in the public’s eye, creating an irrevocable association 

between Guyana and the giant otter that has since been strengthened by recent BBC 

documentaries in the region. Southern Guyana remains one of the top sites in South 

America to see giant otters and as such the species acts as a huge draw to many of 

the eco-tourists that venture to the Rupununi ensuring that there is also an economical 

interest in the survival of the species. 

Rob Pickles’ PhD is an investigation into the phylogeography of the giant otter, 

using mitochondrial DNA to analyse patterns of relatedness between populations 

determining whether there has been any divergence according to drainage basin, 

or whether palaeoclimatic events may have been responsible. It also investigates 

the degree of gene flow between populations which has important implications for 

effective management of the species. 


Figure 9a. Territorial display by a group of giant otters above Corona Falls. Termed ‘periscoping’ 

the behaviour is accompanied by a cacophony of wails and snorts often backed up by a mock 

charge. For the biologist, periscoping allows pictures to be taken of the unique throat patterns 

allowing identification of individuals. 

Figure 9b. Inquisitive adult male giant otter approaching the boat. While some individuals are 

remarkably fearless and will approach to within several yards of the boat, the mood of the group 

is determined by the breeding female. If she feels threatened the group will normally periscope 

and disappear. 


Method 

In surveying the Rewa for signs of giant otters we followed the guidelines of the 

IUCN/SSC Otter Specialist Group (Groenendijk et al 2005). The river was searched for 

sign during drifts downstream, looking out for evidence of holts, latrines or scratch 

walls or for the groups themselves. The position of these was recorded using GPS 

to delineate group territories. Group sizes were obtained by directly counting all 

individuals when a group was encountered in the river. We used two Canon EOS 

400D cameras with 300mm and 500mm lenses to capture throat markings and a Sony 

Handycam mini DV. Giant otters have a unique throat pattern which can be used to 

identify individuals, preventing the same group being counted twice. When an active 

site was located, any faecal deposits evident were collected and stored in ethanol for 

subsequent genetic analysis. 

Results 

In the 65 miles of Rewa Head explored above Corona Falls, we found evidence of 

5 groups with an estimated population size of 35 animals and collected 17 faecal 

samples. Due to the unseasonably heavy rains experienced it proved more difficult 

than anticipated to locate and observe groups. The narrow streams feeding the Rewa 

were full, resulting in groups spending much of their time hunting in these difficult 

to access creeks. We found that groups frequently had latrines at the confluence of 

a forest stream and the main river. Although we did not survey the Lower Rewa for 

giant otters, we did encounter 4 groups and collected 13 faecal samples from them. 

We also observed the neotropical otter (Lontra longicaudis) in the Rewa Head on four 

occasions and encountered two sprainting sites. 

While there currently appears to be no direct threat to the giant otter’s survival in the 

Rewa and the population appears healthy, in informal discussions with fishermen it is 

apparent that they view the giant otter as a competitor. Work in Bolivia, by Beccera- 

Cardona (2006) has shown that in rivers there, there is only a small overlap in fish 

species and size selection by fishermen and giant otters, however the more generalist 

nature of the Guyanese fishermen would inevitably lead to a degree of competition. 

This competition is generally tolerated, with actual killing of otters by villagers being 

rare. However food shortages in unproductive years might exacerbate antagonistic 

feeling towards giant otters leading to conflict. 

In the Lower Rewa evidence that the river might be mined for gold or diamonds was 

recorded. We found claims staked in April 2008 spread over 20 river miles. As this 

report was being prepared the Guyanese Government revoked all claims in the Lower 

Rewa and has put a moratorium on mining throughout both the Rewa Head and Lower 

Rewa. The giant otter is a top predator in its food chain and is thus extremely sensitive 

to mercury bioaccumulation. Mercury concentration has been shown to cause a range 

of neurological disorders, impaired reproduction and immunocompetency (Klenavic et 

al 2008, Fonseca et al 2005). 

Camera Trapping Survey 

In this study we used the Reconyx RC55 camera trap due to its fast ‘wake-up’ time and 

rate of image capture, able to record 1 frame per second. This enables a more accurate 

estimate to be made of animals travelling in groups. The use of digital technology 

proved essential in the high humidity of the forest and despite torrential rains, no 

camera was lost to mould. 2GB Extreme III CF cards were used and proved ample 

to contain all images captured. The traps were triggered by a PIR motion sensor and 

were mounted with an infrared LED illuminator. Camera setup was as follows. Image 

quality: medium; Firing delay: no delay; Firing sensitivity: extremely high. 


Figure 10. Rapidity with which all 17 species of mammal 

recorded in the camera traps were captured. 

14 Biodiversity of the Rewa Head 

Method 

Twelve Reconyx RC55 camera 

traps were set up along the 

Rewa above Corona Falls. Each 

trap was fixed to a tree or stake 

approximately 50cm above the 

ground. The traps were set up in 

pairs, with one on the river bank 

itself facing inland and its partner 

150 metres perpendicular to the 

river bank facing a direction 

estimated to best increase the 

likelihood of capture. Each camera 

was considered a separate 

sampling site for determining the 

Relative Abundance Index (RAI). 

The pairs were arranged 5 miles 

apart and left for a maximum of 

22 days before collection. While 

game trails were not sought for 

in the placement of the traps, local judgment was employed in their positioning 

in order to prevent focusing on dead ground. Due to the strict adherence of the 

5mile/150m rule, we ensured that to some extent the placement of the traps was 

randomised and took in a variety of micro-habitats from dense scrubby marshland 

to hill tops to open riparian bush. 

Figure 11. Layout of the string of camera traps along the river. 

Results 

In total, 5227 camera trap hours were accumulated resulting in 214 triggering events. 

Of these, discounting false triggerings due to movement of leaves by wind or in cases 

where animals had passed too rapidly to be captured, 167 individual animals could 

be identified from 16 species of mammal, 5 species of bird: Black curassow (Crax 

alector), grey-winged trumpeter, (Psophia crepitans), grey-fronted dove, (Leptotila 

rufaxilla), great tinamou (Tinamus major) and cinereous tinamou (Crypturellus 

cinereus); and one species of reptile: the jungle runner (Ameiva ameiva). From the 

raw images of animals in which individual identification or sexing was impossible, 

we filtered the data based on the assumption that multiple firing episodes taken 

at the same site in the same 24 hour period constituted the same animal or group. 

Number of individuals was then estimated from this as 157. Number of estimated 

individuals for each species was then divided by this total to obtain the Relative 

Abundance Index (RAI).

Table 1. Species diversity and relative abundance index of mammals recorded in the camera traps. 

Common Name Latin Name 

Number 

of firings 

Estimated 

number of 

individuals 

Relative 

Abundance 

(%) 

Red-rumped Agouti Dasyprocta cristata 42 28 25.2 

Paca Agouti paca 18 17 15.3 

Green Acouchy Myoprocta exilis 27 15 13.5 

Collared Peccary Tayassu tajacu 2 9 8.1 

Brazilian Tapir Tapirus terrestris 9 9 8.1 

Nine-banded Long-nosed 

Armadillo 

Dasypus novemcinctus 9 9 8.1 

Red Brocket Deer Mazama americana 4 4 3.6 

Ocelot Leopardus pardalis 4 4 3.6 

Common Grey Four-eyed 

Oppossom 

Philander opossum 3 3 2.7 

Common Oppossom Didelphis marsupialis 2 2 1.8 

Jaguarundi Puma yagouaroundi 2 2 1.8 

Margay Leopardus wiedi 2 2 1.8 

Puma Puma concolor 2 2 1.8 

Spiny Rat sp Proechimys sp 2 2 1.8 

Guianan Squirrel Sciurus aestuans 1 1 0.9 

Giant Anteater Myrmecophaga tridactyla 1 1 0.9 

Tayra Eira barbara 1 1 0.9 

17 131 111 100 

Discussion 

The frequency of triggerings were not evenly distributed throughout the line of traps, but it 

appeared that several traps were set up in areas that were ‘dead ground’ with the worst site 

(3.1) only firing three times, with only one triggering event yielding species identification 

shots, while others were in ‘hot spots’. Traps 4.2 and 6.1 proved the most successful, both 

recording 11 species from 30 and 39 triggering events respectively. Trap 4.2 was actually 

set up on a hill, 150m from the river’s edge and proved to be an extremely successful spot. 

All traps except one continued to work well despite the torrential downpours and high 

humidity experienced during the expedition, battery power was between 60-80% when 

the traps were recovered after 22 days and the 2GB CF cards were between 1-40% full. To 

a certain extent, the lack of triggerings made in the poorer sites might reflect inaccurate 

set up. Judging the exact angle at which to point the trap in order to both capture small 

rodents passing in the foreground and anything passing in the background was not always 

successful. We recommend using a laser pen for setting up as this can help to achieve the 

perfect angle. While the company Moultrie have a camera trap on the market with this 

function built in, the lack of the ability to have constant firing function, coupled with a 

slower wake-up time meant we rejected that model for this study. 

There appeared to be no difference in species capture success depending on the 

placement of camera traps whether at the river’s edge, or set 150m inland. The bank 

traps captured a total of 17 species in 79 triggerings, whereas the inland traps captured 

19 species in 91 triggerings. Four species were exclusively caught in the river edge 

traps (Guianan squirrel (Sciurus aestuans), ocelot (Leoprardus pardalis), puma (Puma 

concolor), and jungle runner (Ameiva ameiva) whereas 6 were caught only by the 

inland traps (red brocket deer (Mazama americana), giant anteater (Myrmecophaga 

tridactyla), tayra (Eira barbara), margay (Leopardus weidii), common opossum 

(Didelphis marsupialis) and grey-winged trumpeter (Psophia crepitans)). 

One reason for setting up the traps in a paired string was to test the hypothesis that 

felids follow watercourses and so will be more likely to be captured near to the river 

bank. While our data are not numerous enough to make meaningful statements, out of 

the 10 cats photographed, 7 of them were captured by the river’s edge traps. 


Figure 12. Male puma (Puma concolor) filmed captured 

following a female (tail just visible on far right). 

Figure 14. Inquisitive female Brazilian tapir 

(Tapirus terrestris). 

Figure 16. Rainforest dwelling giant anteater 

(Mymecophaga tridactyla). 


Figure 13. Herd of collared Peccary (Tayassu tajacu). 

Figure 15. Tayra (Eira Barbara). 

Figure 17. Margay (Leopardus wiedii). 

Figure 18. Ocelot (Leopardus pardalis). Figure 19. Jaguarundi (Puma yagouaroundi).

The data reveal a typical situation of high numbers of prey species to predators. Redrumped 

agouti (Dasyprocta cristata), paca (Agouti paca) and green acouchy (Myoprocta 

exilis) were the most abundant, comprising 25.2%, 15.3% and 13.5% respectively of 

mammals recorded. Surprisingly no jaguars (Panthera onca) were recorded despite 

a known high density from previous expeditions. The reason for this is unclear 

although may be related to the unseasonably high water levels experienced during 

the expedition, meaning game would be more dispersed throughout the forest and 

less focussed on the river. In comparing our results with those from Pobawau Creek 

and Cacique Mountains camera trapping sites set up by CI in the Eastern Kanukus RAP, 

it is interesting to note that white-lipped and collared peccaries (Tayassu pecari and 

T.tajacu) were the most abundant species recorded there, whereas they recorded no 

Brazilian tapir (Tapirus terrestris), which is the fifth most abundant species recorded in 

the Rewa Head camera traps. 

When looking at the effectiveness of identifying medium to large mammalian species in 

a short period of time using camera traps, table 1 reveals that of the 17 species observed 

this way, all were recorded after only 12 days of camera trapping. It appears therefore that 

in order to record more species requires either a much longer sampling period, or a much 

broader camera network. This would also give more robust RAI figures. 

Observations 

We found a high diversity of primates, with all of Guyana’s 8 species recorded. Of 

particular importance were the Guianan Shield endemics, the black spider monkey (Ateles 

paniscus) classified as ‘Vulnerable’ by the IUCN, the Guianan saki (Pithecia pithecia) 

and, the Guianan red howler monkey (Alouatta macconnelli), recently upgraded to full 

species, of which over 7 groups were recorded during drift transects. 

Figure 20. Fresh bush dog (Speothos venaticus) print at the entrance to a paca den on the 

riverbank. Rare and elusive animals, bush dog are an indicator of undisturbed habitat. 

Fresh footprints of bush dog (Speothos venaticus) seen investigating the burrow 

of a paca along the banks of a tributary feeding the Rewa are firm evidence for the 

presence of this unusual canid in the Rewa Head. The bush dog is an elusive and 

poorly understood animal, with most data on its behaviour and diet derived from 

anecdotes. In one study on diet in the Brazilian Pantanal, de Souza Lima et al (2009) 

recorded that the predominant prey found in faeces was the nine-banded long-nosed 

armadillo (Dasypus novemcinctus), which appears abundant in the Rewa Head. 

Although its range is large and it is found throughout Amazonia, it is considered to 


occur in low densities throughout that extent. The IUCN red list classifies the species 

as ‘Near Threatened’ being likely to suffer a 10% decline over the following decade due 

to habitat degradation (Zuercher et al 2008). 

Several burrows of the giant armadillo (Priodontes maximus) were found in the Rewa 

Head. This species is classified as ‘Vulnerable’ by the IUCN. 

Figure 21. Brazilian tapir (Tapirus terrestrisi) photographed 10ft from boat. 

Brazilian tapir (Tapirus terrestris) appeared to be abundant in the Rewa Head. During 

drift surveys we observed 5 in total on the banks or in the river. As with curassow 

and paca, the tapirs we encountered appeared remarkably nonchalant about our 

presence, allowing us to approach to within several yards without causing alarm. 

To give a rough guide to the density of these animals in the Rewa Head, along a 40 

mile stretch of river, while conducting drift transects over several days, we recorded 

97 fresh tapir roads, equating to approximately 2.5 fresh roads every river mile. This 

coupled with the fact that they were the fifth most numerous species in the camera 

traps suggests a strong, healthy population. 

Table 2. Comparison of diversity of mammalian orders in three survey sites in Guyana. 

Site Iwokrama Rewa Head Eastern Kanukus 

Reference 


Lim and Ergsrtom 

2004 

Pickles, McCann, Holland 

2009 

Montambault and Missa 

2002 

Survey duration 

(days) 

37 + 49 22 8 

Marsupialis 7 2 11 

Xenarthra 4 4 9 

Primates 5 8 8 

Carnivora 8 10 16 

Perissodactyla 1 1 1 

Artiodactyla 4 2 5 

Rodentia 15 5 9 

44 32 59

Figure 22. Pale-throated three-toed sloth (Dasypus tridactylus) photographed at the river’s edge. 

Jaguar were glimpsed twice above the falls and their presence was noted in fresh 

scratch patches and scats left near camp. However, due to the high level of the river 

following several torrential downpours, there was a lack of exposed rocks where 

they have been filmed basking on previous trips. During a 6 week trip above Corona 

Falls in 2004 for instance, Ashley Holland and Gordon Duncan filmed 10 jaguars at 

extremely close proximity. Jaguarundi (Puma yagouaroundi) was seen once. From 

sightings and camera trap evidence we recorded five of the six species of felid known 

to exist in Guyana, and given the nature of the habitat and lack of disturbance, it is 

likely that the oncilla (Leopardus tigrinus) will exist in the area as well. The cryptic 

pale-throated three-toed sloth (Bradypus tridactylus) was also seen on drift surveys, 

three were recorded in the duration of the expedition. 

In total we recorded the presence of 33 species of non-volant mammal, including 

2 marsupials, 4 xenarthrans, 8 primates, 10 carnivores, 1 perrissodactyl, 2 artiodactyls, 

and 6 rodents, equating to 35% of Guyana’s total non-volant, non-marine mammalian 

fauna. Guyana’s total mammalian species count is 225, 121 of which are bats and 

8 are marine cetaceans. In comparing the results of our survey in the Rewa Head with 

those from other surveys in Guyana such as Iwokrama and the Eastern Kanukus, one 

should note that no small-mammal trapping took place during our expedition and we 

only present in our species list animals recorded during the course of the expedition. 


Chapter 2. Bird Species Diversity and Relative Abundance 

Avian diversity and relative abundance was measured by conducting a series of spot 

counts drifting downstream along 60 miles of the Rewa Head, and through mist netting 

at camps set roughly 12 miles apart along from the East-West Split to Powis Falls. 

For reference we used Steven Hilty’s Birds of Venezuela in conjunction with Robin Restall’s 

Birds of Northern South America and the Smithsonian Institution’s A Field Checklist of 

the Birds of Guyana. In English names we have chosen to follow Hilty’s nomenclature. 

Principal Findings 

• 187 species recorded through drift spot counts and mist netting. This rises to 

251 with the inclusion of the Smithsonian Institution’s 2006 data. 

• 10 Guianan Shield Endemics. 

• Confirmed presence of threatened harpy and crested eagle. 

• High diversity of raptors with 12 species recorded. 

Mist Netting Survey 

We conducted mist net surveys at 5 points along the 60 miles of river on which we 

were focussing our research. We used three 40ft standard BTO NR nets with a mesh 

size of 3cm. These proved fine enough to capture small birds such as antbirds and 

hummingbirds, and strong enough to capture species up to the size of a pigeon. 

Figure 23. Ash and Rob identifying a plain-brown woodcreeper (Dendrocincla fuliginosa). 

Method 

The nets were erected 50-200m from camp in a variety of habitats such as near vine 

tangles, tree falls and along the river edge in order to catch unobtrusive species which 

would not have been recorded during a drift transect. The nets were erected at 6am 

and taken down at 5:30pm during surveys and were checked every hour. Five netting 

sites were used from the East-West Rewa split down to Powis Falls covering a variety 

of habitats from open, scrubby bush, to palm thickets and dense forest. Ashley Holland 

has been identifying birds in the Rewa for several years and he, Ryol Merriman and 

Kevin Alvin had worked previously with the Smithsonian Institution during their 

collecting expedition in 2006 and were adept at removing and identifying birds in the 

nets, being familiar with the majority of species caught. 


Figure 24. A White-plumed Antbird (Pithys 

albifrons). 

Figure 25. Blue-crowned Motmot (Motmotus 

motmota). 

Figure 26a. Rufous-belled antwren (Myrmotherula guttata) and Figure 26b. brown-bellied 

antwren (Myrmotherula gutturalis), two Guianan Shield endemics. 

Figure 27. Rufous-throated antbird (Gymnopithys 

rufigula). 

Figure 28. Pygmy kingfisher, (Chloroceryle 

aenea). 

Figure 29. Variegated antpitta (Grallaria varia). Figure 30. Red-necked woodpecker (Campephilus 

rubricollis) 


Results 

In total 420 mist net hours were accumulated (140 hours per net) at the five netting 

sites. 91 birds were caught, resulting in 41 different species being identified. Four birds 

were unidentified; two of which were likely to have been female long-winged antbirds 

(Myrmotherula longipennis). Twenty-three of the species caught in mist nets were not 

observed during the drift transects. 

The most frequently caught family was the Thamnophilidae with 15 of all species 

and 27% of total number of individuals caught, followed by the Dendrocolaptidae (5 

species) and Trochilidae (4 species). The most common species encountered in the 

nets was the wedge-billed woodcreeper (Glyphorynchus spirurus). 

Drift Spot Count Survey 

Method 

In conducting drift spot count surveys, we divided the river from the East-West Split at 

N2° 37.740’ W58° 37.040’ down to Corona Falls at N3° 10.579’ W58° 40.433’, into 5 mile 

stretches. Each stretch was surveyed once by drifting downstream with three spotters in a 

boat, taking turns at inputting the data, resulting in a single surveyed transect of 60 miles. 

We used a portable mp3 player containing the vocalisations of the birds of Venezuela to 

identify calls and song. We kept to mid-river when it was narrow enough to cover both 

banks, but when the river widened to over 40m we kept within 15m of one bank. To 

standardise the surveys we attempted to maintain a steady speed of around 2 miles per 

hour, by paddling through slower stretches though the speed invariably depended on the 

volume of water flowing. Following heavy rains transect duration was shorter by at least 

half an hour due to the increased flow. Occasionally it was necessary to break up a stretch, 

such as when portaging. When this occurred we halted the count until the obstacle had 

been passed. Spot counts were carried out in the morning, when animal activity was 

greatest. However, due to the logistics of moving camp, several times we had to carry on 

with conducting the surveys into the afternoon, when activity generally declined. 

Figure 31. Crimson topaz (Topaza pella). In total nine 

species of hummingbird were recorded in the Rewa. 


Results 

We recorded over 4000 birds 

during the transects, resulting in 

the identification of 158 species 

through both visual observation 

and vocalisations. Through the 

combination of sightings made 

on drift transects, mist-netting, 

opportunistic sightings and 

vocalisations, we positively identified 

187 species from 48 different 

families. The most diverse family 

observed was the Tyrannidae 

(34 species) closely followed by 

Thamnophilidae (31 species), then 

Accipitridae (11 species), Psittacidae 

(11 species), Ardeidae (10 species) 

and Trochilidae and Thraupidae (9 

species). The most abundant family 

was the Hirudinidae comprising 

20% of total observations, 

followed by the Apodidae, with 

16%, Psittacidae with 10% then 

Icteridae with 5%. 

Discussion 

In August 2006 Ashley Holland led a Smithsonian Institution collecting expedition to the 

Rewa, coordinated by Chris Milensky and Brian Schmidt. They set up two mist netting 

sites, one above Corona Falls at Louis Creek (2 58’ 17” N, 58 35’ 37” W) and the other 

below. Above the falls they erected 20 nets and netted for 10 days. Combining our data

with the Smithsonian’s gives a more complete picture of the region’s avifauna as they were 

there in the wet August, while we were there in January, entering the dry season. In the 

species list we present our observations together with those of the Smithsonian Institute 

for direct comparison. This brings the total number of bird species seen in the Rewa to 250 

and number of families to 53, equating to 31% of all Guyana’s bird species (796). 

The difference in season is most apparent in the presence of migratory species such as 

the Osprey (Pandion haliaetus) and the relative abundance of frugivorous species such 

as the Psittacidae which were no doubt more noticeable in January due to congregations 

forming on fruiting trees. Likewise, whereas the Smithsonian recorded the family Ictericidae 

as Uncommon, we often encountered large flocks of yellow-rumped cacique (Cacicus 

cela), red-rumped cacique (Cacicus haemorrhous) and crested oropendola (Psarocolius 

decumanus) as they were nesting, leading us to surmise that they were Common in the area. 

Of chief interest in the sightings are 10 Guianan Shield endemics, the Guianan toucanet 

(Selenidera culik), green aracari (Pteroglossus viridis), black nunbird (Monasa atra), 

rufous-throated antbird (Gymnopithys rufigula), brown-bellied antwren (Myrmotherula 

gutturalis), rufous-belled antwren (Myrmotherula guttata), caica parrot (pionopsitta caica) 

and black curassow (Crax alector). Two species recorded have particularly small ranges 

within the Guianan Shield ecoregion, Todd’s antwren (Herpsilochmus stictocephalus) 

and little hermit (Phaethornis longuemareus). This expedition also confirms the presence 

of the awesome harpy eagle (Harpia harpyja) and crested eagle (Morphnus guianensis) 

in the Rewa Head. A potential sighting of a dusky purpletuft (Idopleura fusca) is worth 

mentioning, although further confirmation is required that they are found in this area. 

The species’ current known range in Guyana is restricted to Iwokrama Reserve, which 

would make the discovery of a second population extremely important. 

Figure 32. The crested eagle (Morphnus guianensis), classed as 

‘’near threatened” in the IUCN Red List. 

The presence of harpy and 

crested eagle, with good 

observations made reflects the 

pristine nature of the habitat 

of the Rewa Head, with large 

mature kapok trees (Ceiba 

pentandra) providing nesting 

sites and a high abundance 

of primate, sloth and cracid 

prey to sustain the population. 

Shortly after our expedition 

Duane de Freitas reported 

10 harpy sightings in the 

Rewa Head, including several 

pairs, suggesting that these 

birds are breeding above 

the falls. The abundance and 

naivety of cracids, both black 

curassow (Crax alector) and 

blue-throated piping-guan (Pipile cumanensis), favoured game birds, illustrates the fact 

that hunting does not take place in the area. The high diversity of raptors recorded is of 

particular interest, six of which were not recorded by the Smithsonian Institute during their 

collecting expedition in 2006, and again points to a pristine habitat rich in prey. 

When seen in the context of Conservation International’s 2001 Rapid Assessment Program 

to the Eastern Kanukus and Lower Kwitaro (Montambau and Missa 2003), our findings 

become more relevant. CI recorded a total of 264 species in the Lower Kwitaro, Eastern 

Kanukus after combining data from their 2001 RAP with that of Davis Finchs survey in 

1998. Of the combined 250 species from ZSL’s 2009 expedition and the Smithsonian’s 2006 

expedition, 68 were not recorded in the Eastern Kanukus and Lower Kwitaro, these are 

predominantly Ardeidae (6 species), Accipitridae (6 species), Thamnophilidae (8 species), 

Tyrranidae (13 species) and Thraupidae (8 species). This might reflect habitat differences 

due to the range from dense rainforest to scrub and bush patches further up the Rewa 

Head, habitat preferred by species such as the little hermit (Phaethornis longuemareus). 


Chapter 3. Reptile Species Diversity 

No specific herpetological studies took place, however several observations made 

during drift transects or through chance encounters are worth recording. 

Firstly the complete absence of black caiman (Melanosuchus niger) and spectacled 

caiman (Caiman yacare) in the Rewa Head is interesting and is likely to be due to Corona 

Falls acting as a dispersal barrier. The contrastingly high numbers of Schneider’s dwarf 

caiman (Paleosuchus trigonatus) above the falls may be due to their preference for cool, 

fast flowing forest streams rather than ecological release from competition with other 

crocodilians. Magnussun et al (1987) considered there to be resource partitioning between 

dwarf and spectacled caiman as a result of differing habitats and prey selectivity which 

precludes competition from occurring. However, Medem (1971) reported that following 

hunting for skins of black and spectacled caiman from rivers in Colombia, the un-hunted 

dwarf caiman (due to the low value of its skin) expanded its range, so perhaps competition 

does play a role in explaining the pattern seen. Below Corona Falls we observed both black 

and spectacled caiman but no dwarf caiman. The species is known to exist in the Lower 

Rewa, but at much lower densities (Holland unpublished data) and is rare downstream of 

the Kwitaro mouth. 

Figure 33. Schneider’s dwarf caiman (Paleosuchus trigonatus) in typical head-up resting pose. 

With regards to Testudines, most conspicuous in its absence was the giant Amazonian 

Turtle (Podocnemis expansa), classified as ‘Lower risk/conservation dependent’ and 

yellow-spotted sidenecked turtle (Podocnemis unifilis), classified as ‘Vulnerable’, both 

of which were recorded in the Lower Rewa up to Corona Falls, yet as with the spectacled 

and black caiman, absent from the Rewa Head. Another Testudine of particular note 

encountered on a hill in dense forest in the Rewa Head was the yellow-footed tortoise 

(Geochelone denticulata) described as ‘Vulnerable’ in IUCN Red List reports. 

We encountered 6 green anacondas (Eunectes murinus) in the Rewa Head during the 

expedition. Five of them were basking on the river bank while the sixth was actively 

swimming. In order to ascertain our size estimates were correct, we captured a large 

anaconda and measured it, taking three measurements from nose tip to tail tip using a 

length of string and assumed the mean measurement to be accurate. Our estimated length 

of 17ft proved close, but short by 1’2”. The snake’s total length was 18’2”. Unfortunately no 

weight was taken, but the animal’s girth at its thickest point was 27”. The other anacondas 

seen were estimated as 8ft, 15ft, 16ft and two at 17ft. The presence of these very large 

snakes in the area is extremely interesting as in the longest-running study on anacondas in 

the world, in the Venezuelan Llanos, Jesus Rivas captured over 900 animals yet recorded 

few specimens growing larger than 16’ long. There is undoubtedly a good prey base for 

the anacondas in the Rewa Head, with capybara and dwarf caiman plentiful. 


Figure 34. Yellow-footed tortoise (Geochelone denticulata). 

Figure 35. The team measuring a large anaconda. Total 

length was determined as 18’2”. 


Chapter 4. The Future state of the Rewa Head: 

Identification of stake holders 

Tour operators and village communities 

Ashley Holland and Duane de Freitas both take tourists up the Rewa, running around 3 

trips per year to the Lower Rewa and 1-2 trips per year above Corona Falls. Approximately 

15 local guides are employed for these trips. This low level ecotourism is sustainable 

and not detrimental to the Rewa Head. Integrating this tourism with the Amerindian 

villages of Rewa and Yupukari has led to the construction of several purpose-built 

lodges for tourists to stay in resulting in a trickle down of revenue into the villages. In 

terms of livelihood the Lower Rewa is also an important source of fish and game and 

villagers also hold small garden plots in the fertile alluvial soil there. 

The Guyanan Nation 

In terms of ecosystem services, the protection of Guyana’s headwaters must be 

considered as the Rewa is an important limb of the Essequibo drainage. We experienced 

firsthand the effect a downpour in the Kanukus immediately has on the river level, 

which in turn has a knock-on effect on levels in the Rupununi and subsequently, the 

Essequibo. The terrifying fact that 90% of Guyanese live in a narrow coastal region 

including Georgetown, which lies 0.5-1m below sea level points to flooding representing 

a constant and immediate risk. The pattern of weather seasonality in Guyana appears 

to be changing, with shorter dry seasons and prolonged, heavier wet seasons. In 2005 

heavy flooding wracked Georgetown affecting over 200,000 people, with open sewerage 

presenting a huge public health problem. Preserving the forests of the Essequibo’s 

headwaters should be seen as one way of minimising run-off and preventing devastating 

flooding from occurring. The covering of dense forest acts to dampen the rush of water 

into the rivers and help prevent flooding further downstream. 

Small-scale gold dredging 

While the substrate under the forests either side of the Rewa reportedly does not 

contain gold bearing rock, being chiefly composed of sandy loam and so unlikely to 

offer a lucrative large-scale mining opportunity, the accumulation of gold particles and 

also diamonds brought down the Rewa from the Kanuku Mountains will have led to 

fluvial or ‘placer’ deposits suitable for mining using small two-man dredges. The Rewa 

constitutes a succession of mining claims and while travelling to the Rewa Head, we 

Figure 36. Use of a hollow tree trunk as a holt by giant otters coincides with the placement of a 

gold mine claim board. 


ecorded claim boards over 20 river miles registered under the name of ‘DWIGHT’ 

Licence number 3748 1-50 claimed in April 2008. Poignantly, one claim board (pictured) 

was found to have been erected beside a giant otter holt. 

Mineral mining including dredging for gold and diamonds is a central aspect 

of the Guyanese economy. In 2008, Guyana’s total export receipts amounted to 

US$798.4million. The largest export was gold, with earnings of US$203.7million. 

Second largest was sugar (US$133.4million) and third largest bauxite, with earnings 

of US$131.1million. As such the importance of mining to the economy of Guyana 

cannot be underestimated. It is important that areas of land are identified that should 

be ring-fenced from mining due to their ecological significance. Equally important is 

that mining practices are improved to minimise the damage done to any environment 

where mining operations are carried out. 

Gold dredging is typically carried out by 2-4 men and a small pontoon-mounted 

dredge, with a diver operating a nozzle to suck up sediment from the riverbed and the 

sediment then being processed on the river bank. Unfortunately the use of mercury for 

amalgamating the gold particles is still widespread in South America. As a result of the 

process of extraction, mercury is lost into the watercourses where, due to biochemical 

interactions, it can be converted into the highly toxic methylmercury and absorbed by 

aquatic life six times easier than the inorganic form (Committee on the Toxicological 

Effects of Methylmercury 2000). The toxic effect of mercury, as a result of bioaccumulation, 

has been well documented and can lead to neurological and organ failure and impaired 

reproduction. Klenavic et al. (2008) found that in wild mink (Mustela vison) and North 

American river otters (Lontra canadensis) high mercury concentration was associated 

with higher parasite burden, suggesting the animals were immunocompromised. 

The dredging itself erodes river banks and results in large sediment plumes in the 

watercourse, leading to smothering of benthic river fauna and flora. 

In 2005 The Geology and Mines Commission released the Mining (Amendment) 

Regulations that aim to improve the environmental practices of all mining operations. 

As part of that amendment a dredge operator can be fined US$350 for mercury 

seepage and the operation shut down. Since November 2008, an Environmental 

Bond of US$480 must be paid before operations begin and at the UN meeting of 

Environmental Ministers in Nairobi in late February 2009, Guyana became a signatory 

in a legally binding treaty aimed at slashing the use of mercury in mining. 

Currently, for small-scale river dredging operations, a river mile is extremely cheap to 

buy, working out at US$20 per mile for the first year and US$10 each succeeding year. 

Including the associated costs of mining permits and licences, to buy the claims for 

the entire Rewa Head would amount to little more than US$1400 for the first year and 

US$1050 for each successive year. 

Oil Drilling 

The Canadian company Groundstar Resources Ltd has been exploring the Rupununi 

and Upper Takutu-Upper Essequibo District for oil and gas reserves since 2005, 

holding the right to exploration and extraction of oil and natural gas in 780,000ha 

of land, part of which includes the Rewa (Source: GGMC Official Gazzette). In March 

2008 the company entered into a farm-in agreement with Canacol Energy Ltd under 

the terms of which Canacol stumps up the initial exploratory costs in return for a 

55% interest stake in the block. Groundstar currently has 3 prospects it is looking 

to exploit containing an estimated 55billion barrels of oil and drilling is expected to 

begin this year following exploratory wells being sunk at the Rewa and Karanambu 

prospects. As yet however, there is no absolute certainty that it will be commercially 

viable to extract the oil (Source: www.scandoil.com, www.rigzone.com). 

Groundstar has apparently begun community consultation and environmental impact 

management. As with the issue of logging, the presiding concern is the development 

of roads and the bringing in of workers to the area. It must be recognised that there are 

benefits to the community from the drilling in terms of local employment in Rewa Village 


itself and the access road which will make it easier for villagers to travel to Lethem, the 

nearest town. However it is of prime concern that the development of the wells should be 

monitored by an objective assessor to ensure that environmental standards are kept. 

Logging 

Simon and Shock International LLC (SSI) is a US based timber company specializing in 

expensive tropical hardwoods for high-end markets. In January 2008 the company bought 

up 400,000 hectares of logging concessions in the headwaters of the Rewa and Essequibo 

rivers with the intention of extracting species such as greenheart (Chlorocardium 

rodiei) and purpleheart (Peltogyne sp). The western section of the logging concession 

incorporates the entirety of the Rewa Head and includes the right banks of the Kwitaro 

and Lower Rewa. The 80,000ha Conservation International concession nestles between 

the East and West logging concessions in the Upper Essequibo. 

As part of a US$45 million project, SSI announced its intention to build a state-of-the-art 

saw mill in Linden, northern Guyana. This mill is purported to be the most technologically 

advanced in the world, recovering an estimated 75% of timber from logs as opposed to 

30-40% which is typical in Neotropical mills. This is achieved using a network of lasers 

and computer-guided saws to make the cuts which optimise output. The aim of the mill, 

as explained by Kelly Simon, CEO of Simon and Shock, is to completely eliminate waste. 

Sawdust will be used to fire the kilns and ash will be given to farmers as fertiliser. SSI 

state that the new laser-guided milling technology at the Linden saw mill will result in 

half the number of trees needed to be felled to produce the same volume of timber (SSI 

figures 2007). Although doubts have been expressed over the efficacy of the new mill 

with tropical hardwoods and the recovery estimates claimed. 

In discussions with Kelly Simon, a suite of measures designed to minimise the impact 

of logging were mentioned and the company is evidently keen to portray itself as one 

of the most sustainable and least environmentally damaging logging firms operating 

in South America. At the practical level, measures such as positioning the saw mill in 

Linden in the industrialised north, rather than in the forest itself will negate the need for 

workers to stay in the forest and prevent a creep in of small-scale exploiters. Foresters 

are apparently to be recruited from Annai and bussed in by morning and out by 

evening, while Brinks Security on the road entering the concession will check workers 

for weapons and game and will have the power to arrest poachers. The use of narrow 

forwarders and cable skidders will minimise damage to the ground and surrounding 

trees when logs are removed. SSI have stated that they will leave a set-back of 200yds 

from streams to protect the drainages, six times the proscribed distance, and intend to 

leave ‘biodiversity banks,’ islands of forest within the concession which will be left to 

act as reservoirs and fail-safes for biodiversity. 

If all measures are carried out as stated, the impact on the forest ecosystem will be 

minimised to a degree. However, there are important considerations to take. Namely, 

working and making a profit out of 400,000 hectares of forest would require a large work 

force, likely larger than the small village of Annai could supply. This would necessitate 

bringing in workers, perhaps settling them in Annai. Feeding these workers protein 

will then become an issue, and it will be extremely difficult to prevent any poaching 

at all from occurring. While armed security at a checkpoint on the road will prevent 

vehicles from entering, poachers on foot would simply be able to hike around the 

checkpoint. Logging the concession will necessitate creating a network of roads to 

bring the forest machinery in and the logs out. Due to the nature of the Parishara area, 

the most likely access point to the concession, the roads will have to be substantial. 

One estimate suggests they will need to be 10-15ft high. Furthermore transporting 

the logs to Linden would most likely be carried out using double trailered road trains 

with a gross weight of 110 tons which local sources have pointed out, would require 

55 bridges to be rebuilt at an estimated cost of US$1 million per bridge. The Lethem 

to Georgetown road would also have to be widened to incorporate the size of these 

trucks. That coupled with the 400 miles of road needed to traverse between the SSI 

concession and the Linden saw mill may well make the venture uneconomical. 


Figure 37. The area leased to Groundstar Resources for oil drilling totals 780,000ha of land and 

includes two prospects, one near Karanambu lands and the other near Rewa village. (Source: 

Takutu Basin: Groundstar PPL www.groundstarresources.com/country.html) 

Simon and Shock International has been leased 400,000ha of land including the entirety of the Rewa 

Head. (Source: Forest Resources Information Unit, Guyana Forestry Commission). 


While outwardly selective logging can appear to cause minimal environmental 

degradation, un-detectable from fly-overs, the removal of large economic species will 

alter the canopy structure and the reduction in leaf-fall from such key trees has been 

shown by Villela et al (2006) in the eastern Brazilian forests to cause a reduction in 

nutrient cycling. If poorly managed, skidding out logs can damage trees and saplings 

and the compacted furrows caused by logging machinery can alter surface run-off, 

leading to erosion. The construction of the roads and bridges as well as the skidding 

trails will without doubt impact negatively on sensitive species such as bush dog 

(Speothos venaticus) as well as ground nesting birds such as tinamous (Tinamidae). 

The economic impact of SSI’s acquisition of the Upper Rewa-Essequibo concessions 

should not be underestimated. The company has stated that it is pumping $45million 

into this project and so one can expect that when logging begins, the returns are 

significant. Under the terms of the agreement with the Guyanese government, 

all timber extracted from the forests will not leave Guyana, but will be worked incountry, 

allowing the nation to maximise the revenue from its forests. The villagers 

of Annai and a workforce in Linden will benefit from the project through employment. 

However, whether the governmental income from logging the concession exceeds 

that of receiving payments from REDD to hold on to the concession intact has been 

challenged by Rhett Butler (see Butler 2008) who reports that in fiscal terms the forests 

could be worth more to Guyana standing. 

Figure 38. In the dry season huge sandy beaches are exposed in the Lower Rewa, providing a nesting 

ground for giant South American river turtles (Podocnemis expansa). The superabundance of eggs laid 

in these sand banks is a boon which many forest species time their breeding cycle to coincide with. 


Chapter 5. Conservation value of the Rewa Head 

In the 22 days spent above Corona Falls we recorded the presence of 33 species of 

mammal, equating to 35% of all non-volant mammal species in Guyana. The combined 

ZSL/SI figure of 250 bird species represents 31% of Guyana’s total bird species count. 

Of those, 11 were found to be Guianan Shield endemics. Following further surveying 

of the area including the use of small-mammal traps these figures are certain to rise. 

These initial findings strongly suggest that the Rewa Head is a region of outstanding 

biological richness and deserves international recognition. 

Of Guyana’s 28 non-marine species of mammal, bird and reptile classified as 

‘conservation dependent’ or worse, we recorded 10 present in the Rewa Head (2 birds, 

8 mammals, 1 reptile) and 3 were found to exist in the Lower Rewa up to Corona Falls 

(black caiman, Melanosuchus niger; Giant South American river turtle, Podocnemis 

expansa and the yellow-spotted side-necked turtle, Podocnemis unifilis). Other species 

such as the blue-cheeked Amazon (Amazona dufresniana), oncilla (Leopardus tigrinus) 

and white-lipped peccary (Tayassu peccary) are highly likely to be found in the Rewa 

Head following further surveying. 

Table 5. Threatened species of Guyana (IUCN Red List 2008). Yellow highlight indicates presence 

above Corona Falls, orange indicates presence below Corona Falls. 

Mammals 

Common Name Latin name Status 

Black Spider Monkey Ateles paniscus Vulnerable 

Oncilla Leopardus tigrinus Vulnerable 

Margay Leopardus wiedii Near Threatened 

Giant Anteater Myrmecophaga tridactyla Near Threatened 

Venezuelan Fish-eating Rat Neusticomys venezuelae Vulnerable 

Jaguar Panthera onca Near Threatened 

Giant Armadillo Priodontes maximus Vulnerable 

Giant Otter Pteronura brasiliensis Endangered 

Bush Dog Speothos venaticus Near Threatened 

Brazilian Tapir Tapirus terrestris Vulnerable 

White-lipped Peccary Tayassu pecari Near Threatened 

Spectral Bat Vampyrum spectrum Near Threatened 

Birds 


Blue-cheeked Amazon Amazona dufresniana Near threatened 

Sun Parakeet Aratinga solstitialis Endangered 

Red Siskin Carduelis cucullata Endangered 

Rio Branco Antbird Cercomacra carbonaria Near Threatened 

Olive-sided Flycatcher Contopus cooperi Near Threatened 

Harpy Eagle Harpia harpyja Near Threatened 

Crested Eagle Morphnus guianensis Near Threatened 

Orinoco Goose Neochen jubata Near Threatened 

Great-billed Seed-finch Oryzoborus maximiliani Near Threatened 

Bearded Tachuri Polystictus pectoralis Near Threatened 

Hoary-throated Spinetail Synallaxis kollari Endangered 

Buff-breasted Sandpiper Tryngites subruficollis Near Threatened 

Reptiles 


Yellow-footed tortoise Geochelone denticulata Vulnerable 

Black Caiman Melanosuchus niger 

LowerRisk/conservation 

dependent 

Giant South American Turtle Podocnemis expansa 

LowerRisk/conservation 

dependent 

Yellow-spotted Sideneck Turtle Podocnemis unifilis Vulnerable 


From our brief visit to the Rewa Head it is clear that the region is biologically rich, containing 

both Guianan Shield endemics and threatened species, with a naivety in wild animals not 

seen in hunted areas. A direct comparison of our results with those from the CI RAP to 

the Eastern Kanukus in 2001 highlights the fact that there are important species which we 

recorded in the Rewa Head which have not yet been recorded in the Eastern Kanukus. 

Conservation Recommendations 

In Conservation International’s 2001 Eastern Kanukus RAP (Montambaut and Missa 

2002), they proposed creating a “corridor of conservation” extending from the Western 

Kanukus across Southern Guyana to the Suriname border. Since then the Kanuku 

Mountains Protected Area has been proposed and is now in the planning stages and 

CI has leased up 80,000ha of logging concession in the Upper Essequibo. 

The Rewa Head and the Lower Rewa are both important in terms of their biodiversity. 

The isolated nature and natural protection afforded the Rewa Head by the string of falls 

and cataracts makes the place appealing when considering preserving the area in law. 

The area is worth recognising for the outstanding wildlife viewing for dedicated birdwatchers 

and adventurous eco-tourists. Since Ashley Holland and Duane de Freitas 

have been taking paying customers up the Rewa, the villagers of Rewa and Yupukari 

have been benefitting from a supplementary income, from paid guides to managing 

tourist lodges. The reason the guests go out to the interior, and to the Rewa in particular, 

is specifically to view wildlife which elsewhere has been pushed out or made shy 

through development and hunting. It is the extraordinary naivety of species such as 

tapir and jaguar and the ease with which they are seen that is the Rewa Head’s chief 

selling point. 

A crucial recommendation of this report is that further scientific studies be carried 

out in the area. The authors have contacted the conservation organisation Operation 

Wallace about the potential of establishing a yearly expedition to the Rupununi. 

Operation Wallacea organise a series of biological and social science expeditions 

that operate in remote locations across the world. These expeditions are designed 

with specific wildlife conservation aims in mind - from identifying areas needing 

protection, through to implementing and assessing conservation management 

programmes. Operation Wallacea work very closely with the indigenous peoples 

inhabiting all of their study sites and are particularly concerned that it is the local 

inhabitants who benefit from their presence there. The data extracted during these 

expeditions are published in peer reviewed journals as well as in popular science 

magazines. The publication of data from the biodiversity rich Rupununi region will 

in turn encourage further scientific teams, film crews and eco-tourists to visit the 

area, which will bring yet more funds into the local communities. We consider the 

establishment of regular expeditions to designated research stations around Region 

9 as highly important in the future sustainability of the area and the broadening of 

incomes within local villages. 

As well as the benefits to the local communities to be afforded through well managed 

tourism and scientific studies, the Lower Rewa is also extremely important from a 

livelihoods perspective. Fish, turtle eggs and game are all taken from this stretch. 

Therefore there is a vested interest to maintain that source of protein. The fact that 

no-one apart from Ashley Holland and Duane de Freitas go above Corona Falls may 

mean that the area acts as a huge source population for many game species which 

then disperse to the Lower Rewa where they are hunted. 

These two facets of the area: well-managed eco-tourism bringing financial income to 

the local villages and the maintenance of a hunting base can be employed to benefit 

the Amerindian People as well as the wildlife and natural resources themselves. 


Figure 39. A relict leviathan, the anaconda’s future above Corona Falls is uncertain. 


e f e r e n C e s 

Becerra Cardona M and Van Damme P. (2006) Identificacion de especies de peces 

(Erythrinidae, Cichlidae y Serrasalminae) en la dieta de la londra (Pteronura brasiliensis) 

en el rio Paragua (Bolivia). Diploma Thesis: Universidad Mayor de San Simon, 

Cochabamba, Bolivia 

Braun MJ, Finch DW, Robbins MB and Schmidt BK. (2000). A Field Checklist of the 

Birds of Guyana. Centre for the Study of Biological Diversity, University of Guyana, 

Georgetown, Guyana; Biological Diversity of the Guianas Progrma, National Museum 

of Natural History, Smithsonian Institute, Washington DC. 

Carlos J, Duarte S and Rebelo GH. (1985). Carnivore skins held in Brazil. Traffic Bulletin. 

7 (1) 16-17 

Carter SK and Rosas FCW. (1997). Biology and conservation of the giant otter Pteronura 

brasiliensis. Mammal Review 27 (1) 1-26 

Committee on the Toxicological Effects of Methylmercury, Board on Environmental 

Studies and Toxicology, National Research Council. (2000). Toxicological Effects of 

Methylmercury. National Academies Press 

Ellenbroek A (1996). Rainforests of the Guyana Shield: Evergreen or forever gone? 

BOS NiEuWSLETTER Vol. 15(2), no. 34, pp. 7-12. 

Emmons LH & Feer F (1997) Neotropical Rainforest Mammals. A Field Guide, Second 

Edition. University of Chicago Press: Chicago. 

Environmental Protection Agency of Guyana (2007) National Biodiversity Action 

Plan II: A continued programme for action by stakeholders towards the conservation 

and sustainable use of biodiversity. Environmental Protection Agency of Guyana, 

Georgetown, Guyana 

Fonseca FRD, Malm O, Waldemarin H (2005). Mercury levels in tissue of giant otter 

(Pteronura brasiliensis) from the Rio Negro, Pantanal, Brazil. Environmental Research 

98 368-371 

Garda AA and Cannatella DC. (2007). Phylogeny and biogeography of paradoxical frogs 

(Anura, Hylidae, Pseudae) inferred from 12S and 16S mitochondrial DNA. Molecular 

Phylogenetics and Evolution doi:10.1016/j.ympev.2006.11.028 

Bradshaw M and Safve V. (2009) Under the cover of forest certification: how the Forest 

Stewardship Council failed to prevent the destruction of high conservation value 

forests in Sweden. Greenpeace Nordic, Stockholm 

Greenwood S, McGavin G and Alexander E (2007). Report on the visit of the BBC to the 

forest of the Upper Essequibo. BBC Natural History Unit 

Griffiths T. (2008). Seeing ‘REDD’? Forests, climate change mitigation the rights of 

indigenous peoples Update for Pozna (UNFCCC COP 14). Forest Peoples Programme 


Groenendijk J, Hajek F, Duplaix N, ReutherC, van Damme P, Schenck C, Staib E, Wallace 

R, Waldemarin H, Notin R, Marmontel M, Rosas F, Ely de Mattos G,Utreras V, Lasso 

G, Jacques H, Matos K, Roopsind I, Botello JC (2005). Surveying and monitoring 

distribution and population trends of the giant otter (Pteronura brasiliensis). Guidelines 

for a standardisation of survey methods as recommended by the giant otter section of 

the IUCN/SSC Otter Specialist Network. Habitat 16: 1-100 

Harris MA, Tomas W, Mourao G, da Silva C, Guimaraes E, Sonoda F and Fachim E. 

(2005). Safeguarding the Pantanal wetlands: threats and conservation initiatives. 

Conservation Biology 19:(3) 714-720 

Hilty S. (2002). Birds of Venezuela. Christopher Helm: London 

Klenavic K, Champoux L, O’Biren M, Daoust PY, Evans RD and Evans HE. (2008). Mercury 

concentrations in wild mink (Mustela vison) and river otters (Lontra canadensis) collected 

from eastern and Atlantic Canada: Relationship to age and parasitism. Environmental 

Pollution 156:(2) 359-366 

Lim BK and Ergstrom MD. (2001) Species diversity of bats (Mammalia: Chiroptera) in 

Iwokrama Forest, Guyana, and the Guianan subregion: implications for conservation. 

Biodiversity and Conservation. 10(4) 613-657 

Lim BK and Ergstrom MD. (2004) Mammals of Iwokrama Forest. Proceedings of the 

Academy of Natural Sciences of Philadelphia. 154:(1) 71-108 

Magnusson WE, Veira da Silva & Lima AP. (1987). Diets of Amazonian crocodiles. 

Journal of Herpetology. 21:(2) 85-95 

Medem, F. 1971. The reproduction of the Dwarf Caiman, Paleosuchus palpebrosus. In 

Proceedings of the 1st Meeting of the CSG 

Montambaut JR & Missa O (Eds). (2002) A Biodiversity Assessment of the Eastern 

Kanuku Mountains, Lower Kwitaro River, Guyana. RAP Bulletin of Biological Assessment. 

Conservation International, Washington DC. 

Office of the President, Republic of Guyana (2008). Saving the World’s Forests today: 

Creating Incentives to Avoid Deforestation 

Office of the President, Republic of Guyana (2009). A Low carbon development strategy: 

Transforming Guyana’s economy while combating climate change. 

Restall R, Rodner C and Lentino M. Birds of Northern South America: An Identification 

Guide. Christopher Helm: London 

RigZone (2008). brazAlta Reviews Onshore Guyana Farm-in, Resource Report http:// 

www.rigzone.com/news/article.asp?a_id=69062 doi:06/11/2008 

Rowcliffe JM, Field J, Turvey ST and Carbone C. (2008). Estimating animal density 

using camera traps without the need for individual recognition. Journal of Applied 

Ecology.45: 1228-1236 


Saatchi SS, Houghton RA, Dos Santos Alvala RC, Soares JV and Yu Y (2007). Diversity of 

above ground live biomass in the Amazon Basin. Global Change Biology. 13: 816-837 

Scand-oil (2008) Groundstar provides update on Egypt and Guyana prospects http:// 

www.scandoil.com/moxie-bm2/news/groundstar-provides-update-on-egypt-andguyana-pro.shtml 

doi.17/04/2008 

Schenk C (1996). Vorkommen, habitatnutzung und schutz des riesenotters Pteronura 

brasiliensis in Peru. PhD thesis: University of Munich 

Schulte-Hebruggen B and Davies G. (2006). Wildlife Certification and Tropical Timber 

Certification. ZSL Conservation Report No. 6. Zoological Society of London, London 

Simon and Shock International LLC (2007). Sustainable Yield Milling and Management 

in the Tropics. Michigan, USA 

Tortoise & Freshwater Turtle Specialist Group 1996. Geochelone denticulata. In: IUCN 

2008. 2008 IUCN Red List of Threatened Species. www.iucnredlist.org Downloaded on 

19 March 2009. 

Verweij P, Schouten M, van Beukering P, Triana J, van der Leeuw K and Hess S. (2009). 

Keeping the Amazon Forests Standing: A matter of values. WWF, The Netherlands 

Villela DM, Nascimento MT, de Araga LEOC and de Gama DM. (2006). Effect of selective 

logging on forest structure and nutrient cycling in a seasonally dry Brazilian Atlantic 

forest. Journal of Biogeography. 33: 506-516 

Zuercher GL, Swarner M, Silveira L & Carrillo O. (2008). Speothos venaticus. In: IUCN 

2008. 2008 IUCN Red List of Threatened Species. www.iucnredlist.org Downloaded on 

19 March 2009. 

Websites 

Butler R. (2008) www.mongabay.com 

http://news.mongabay.com/2008/0221-guyana.html accessed 10/03/09 

http://www.groundstarresources.com/country.html accessed 25/02/09 

Guyana forestry commission http://www.ggmc.gov.gy/ Guyana Geology and Mines Commision 

High Conservation Value Forests website www.hcvfnetwork.org 

Guiana Shield Initiative www.guianashield.org 


ap p e n d i x i 

Mammalian Diversity 

In the table the evidence is described as S sighting, V vocalisation or I indirect evidence 

such as footprints, scats or burrows. 

English Name Scientific Name 

Opossums Didelphiae 

ZSL Expedition 2009 

Evidence 

Common Grey Four-eyed Opossum Philander opossum S,C 

Common Opossum Didelphis marsupialis C 

Sloths Edentata 

Pale-throated Three-toed Sloth Bradypus tridactylus S 

Anteaters Myrmecophagidae 

Giant Anteater Myrmecophaga tridactyla C 

Armadillos Dasypodidae 

Nine-banded Long-nosed Armadillo Dasypus novemcinctus C,I 

Giant Armadillo Priodontes maximus I 

Marmosets and Tamarins Callitrichidae 

Golden-handed Tamarin Seguinus midas S 

Monkeys Cebidae 

Brown Capuchin Cebus apella S 

Wedge-capped Capuchin Cebus olivaceus S 

Common Squirrel Monkey Saimiri sciureus S 

Guianan Red Howler Monkey Alouatta macconnelli S,V 

Guianan Saki Pithecia pithecia S 

Red-backed Bearded Saki Chiropotes chiropotes S 

Black Spider Monkey Ateles paniscus S,V 

Dogs Canidae 

Bush Dog Speothos venaticus I 

Racoon Family Procyonidae 

South American Coati Nasua nasua S 

Mustelids Mustelidae 

Giant Otter Pteronura brasiliensis S,I 

Neotropical Otter Lontra longicaudis S,I 

Tayra Eira barbara C 


Cats Felidae 

Jaguar Panthera onca S,C,I 

Puma Puma concolor C 

Ocelot Leopardus pardalis C 

Margay Leopardus wiedi C 

Jaguarundi Felis Jaguarundi S,C 

Deer Cervidae 

Red Brocket Deer Mazama americana C 

Peccaries Tayassuidae 

Collared Peccary Tayassu tajacu S,C,I 

Tapirs Tapiridae 

Brazilian Tapir Tapirus terrestris S,C,I 

Squirrels Sciuridae 

Guianan Squirrel Sciurus aestuans C 

Capybaras Hydrochaeridae 

Capybara Hydrochaeris hydrochaeris S,I 

Paca Agoutidae 

Paca Agouti paca S,C,I 

Agoutis and Acouchys Dasyproctidae 

Red-rumped Agouti Dasyprocta cristata S,C,I 

Green Acouchy Myoprocta exilis C 

Spiny rats Echimyidae 

Spiny tree rat Lonchothrix emiliae S 


ap p e n d i x ii 

Avian Diversity and Relative Abundance 

In ascertaining the abundance of each species we followed the Smithsonian’s guide: 

C Common; more than 20 individuals encountered daily in prime habitat and season 

F Fairly common; 5-20 individuals encountered daily in prime habitat and season 

U Uncommon; present in small numbers (fewer than 5 individuals per day); not 

encountered daily even in prime habitat and season 

S Scarce; only occasionally encountered in small numbers even in prime habitat 

and season 

In the table the evidence of the bird is described as S Sighting, V vocalisation, C 

Camera Trap or M mist net. In many cases the vocalisation is more diagnostic than 

a brief sighting and playback was successfully used on a number of occasions to 

identify birds, in particular cryptic understory species such as Todd’s Antwren and the 

Helmeted Pygmy tyrant. 

English Name Scientific Name 

Tinamous Tinamidae 

ZSL 

Expedition 

Jan 2009 

Smithsonian 

Expedition 

Aug 2006 

Evidence 

Great Tinamou Tinamus major S F V, C 

Cinereous Tinamou Crypturellus cinereus U S V, C 

Variegated Tinamou Crypturellus variegatus S F V 

Anhingas Anhingidae 

Anhinga Anhinga anhinga F F S 

Cormorants Phalacrocoracidae 

Neotropical Cormorant 

Phalacrocorax 

brasiliensis 

S S S 

Herons Ardeidae 

Zigzag Heron Zebrilus undualtus S 

Rufescent Tiger-Heron Tigrisoma lineatum U U S 

Fasciated Tiger-Heron Tigrisoma fasciatum S U S 

Cocoi Heron Ardea cocoi F F S 

Little Blue Heron Egretta caerulea S S 

Cattle Egret Bubulcus ibis S 

Great Egret Aredea alba S S 

Agami Heron Agamia agami S S 

Striated Heron Butorides striatus U U S 

Capped Heron Pilherodias pileatus S U S 

Storks Ciconiidae 

Wood Stork Mycteria americana S S 

Ibises Threskiornithidae 

Green Ibis 

Mesembrinibis 

cayennensis 

F C S 

Vultures Cathartidae 

Black Vulture Coragyps atratus U U S 

Turkey Vulture Cathartes aura S S 

Greater Yellow-headed 

Vulture 

Cathartes melanbrotus F F S 

King Vulture Sarcoramphus papa F F S 


Hawks, Eagles Accipitridae 

Swallow-tailed Kite Elanoides forficatus F S S 

Double-toothed Kite Harpagus bidentatus S 

Grey-headed kite Leptodon cayanensis S S 

Plumbeous Kite Ictinia plumbea S S S 

Great Black-Hawk Buteogallus urubitinga U U S 

White Hawk Leucopternis albicollis U S 

Roadside Hawk Buteo magnirostris S U S 

Short-tailed Hawk Buteo brachyurus S S 

Tiny Hawk Accipiter superciliosus S S 

Harpy Eagle Harpia harpyja S S 

Ornate Hawk Eagle Spizaetus ornatus S S 

Ospreys Pandionidae 

Osprey Pandion haliaetus S S 

Falcons, Caracaras Falconidae 

Lined Forest-Falcon Micrastur gilvicollis U 

Collared Forest-Falcon 

Micrastur 

semitorquatus 

S S 

Black Caracara Daptrius ater U U S 

Red-throated Caracara Ibycter americanus U F S,V 

Bat Falcon Falco rufigularis U F S 

Curassows, Guans Cracidae 

Little Chachalaca Ortalis motmot F U S,V 

Black Curassow Crax alector F U S,V,C 

Blue-throated Piping-Guan Pipile cumanensis U F S,V 

Quails Odontophoridae 

Marbled Wood-Quail 

Odontophorus 

gujanensis 

U 

Rails Rallidae 

Grey-necked Wood-Rail Aramides cajanea S S V 

Sungrebes Heliornithidae 

Sungrebe Heliornis fulica S U S 

Sunbitterns Eurypygidae 

Sunbittern Eurypyga helias S U S 

Trumpeters Psophidae 

Grey-winged Trumpeter Psophia crepitans S U S,V,C 

Sandpipers Scolopacidae 

Spotted Sandpiper Actitis macularia U F S 

Pigeons, Doves Columbidae 

Plumbeous Pigeon Columba plumbea F C V,S 

Ruddy Pigeon Columba subvinacea F C V,S 

Grey-fronted Dove Leptotila rufaxilla F U V,S,M,C 

Ruddy Quail-Dove Geotrygon montana F 

Parrots Psittacidae 

Painted Parakeet Pyrrhura picta C C S 

Blue-and-Gold Macaw Ara ararauna F U S 

Red-and-green Macaw Ara chloropterus F F S 


Scarlet Macaw Ara macao F U S 

Golden-winged Parakeet 

Brotogeris 

chrysopterus 

C C S 

Blue-headed parrot Pionus menstruus C S 

Caica Parrot Pionopsitta caica F C S 

Orange-winged Parrot Amazona amazonica C U S 

Yellow-crowned Parrot Amazona ochrocephala U 

Mealy Parrot Amazona farinosa F S 

Red-fan Parrot Deroptyus accipitrinus F F S 

Cuckoos Cuculidae 

Squirrel Cuckoo Piaya cayana U F S 

Little Cuckoo Piaya minuta S S 

Greater Ani Crotophaga major S U S 

Typical Owls Strigidae 

Tawny-bellied Screech-Owl Otus watsoni U 

Spectacled Owl Pulsatrix perspicillata S U V 

Amazonian Pygmy-Owl Glaucidium hardyii F 

Nighthawks, Nightjars Caprimulgidae 

Short-tailed Nighthawk 

Lurocalis 

semitorquatus 

U U S 

Common Pauraque Nyctidromus albicollis F S 

Blackish Nightjar 

Caprimulgus 

nigrescens 

F U S 

Potoos Nyctibiidae 

Great Potoo Nyctibius grandis S S 

Swifts Apodidae 

Band-rumped Swift Chaetura spinicauda C C S 

Grey-rumped Swift Chaetura cinereiventris C S 

Hummingbirds Trochilidae 

Eastern Long-tailed Hermit 

Phaethornis 

superciliosus 

U U S,M 

Straight-billed Hermit Phaethornis bourcieri U 

Reddish Hermit Phaethornis ruber F 

Little hermit 

Phaethornis 

longuemareus 

S S,M 

Gray-breasted Sabrewing 

Campylopterus 

largipennis 

S S S,M 

White-necked Jacobin Florisuga mellivora U 

Fork-tailed Woodnymph Thalurania furcata S U M 

Crimson Topaz Topaza pella S S S 

Black-eared Fairy Heliothryx aurita S 

Trogons Trogonidae 

White-tailed Trogon Trogon viridis F F S,V 

Violaceous Trogon Trogon violaceus S U S,V 

Collared Trogon Trogon collaris F 

Masked Trogon Trogon personatus U 

Black-tailed Trogon Trogon melanurus S S 

Motmots Momotidae 

Blue-crowned Motmot Momotus momota F F S, V 


Kingfishers Alcedinidae 

Ringed Kingfisher Ceryle torquata U C S 

Amazon Kingfisher Chloroceryle amazona F C S,M 

Green Kingfisher 

Chloroceryle 

americana 

F U S 

Green-and-Rufous Kingfisher Chloroceryle inda S U S 

Pygmy Kingfisher Chloroceryle aenea S S S,M 

Puffbirds Bucconidae 

Guianan puffbird 

Notharchus 

macrorhyncus 

S S 

Collared Puffbird Bucco capensis S U S 

White-chested Puffbird Malacoptila fusca U 

Black Nunbird Monasa atra F F S 

Swallow-wing Puffbird Chelidoptera tenebrosa C C S 

Jacamars Galbulidae 

Green-tailed Jacamar Galbula galbula F U S, V 

Yellow-billed Jacamar Galbula albirostris S F S,M 

Paradise Jacamar Galbula dea S U S 

Great Jacamar Jacamerops aurea S U S,M 

Brown jacamar Brachygalba lugubris F S, V 

Barbets, Toucans Ramphastidae 

Green Aracari Pteroglossus viridis S S 

Black-necked Aracari Pteroglossus aracari S U S 

Guianan Toucanet Selenidera culik S U S 

Channel-billed Toucan Ramphastos vitellinus F C S, V 

White-throated Toucan Ramphastos tucanus C C S, V 

Woodpeckers Picidae 

Lineated Woodpecker Dryocopus lineatus S S S 

Golden-collared Woodpecker Veniliornis cassini U 

Yellow-throated Woodpecker Piculus flavigula F 

Chestnut Woodpecker Celeus elegans S F S 

Waved Woodpecker Celeus undatus S S S 

Cream-colored Woodpecker Celeus flavus U 

Red-necked Woodpecker 

Campephilus 

rubricollis 

S F S,M 

Crimson-crested Woodpecker Campephilus 

melanoleucos 

U F S 

Ovenbirds Furnariidae 

Cinnamon-rumped Foliagegleaner 

Philydor pyrrhodes S 

Rufous-rumped Foliagegleaner 

Philydor erythrocercus F 

Buff-throated Foliage-gleaner Automolus 

ochrolaemus 

F 

Chestnut-crowned Foliagegleaner 

Automolus rufipileatus U V 

Plain Xenops Xenops minutus U 

Woodcreepers Dendrocolaptidae 

Plain-brown Woodcreeper 

Dendrocincla 

fuliginosa 

S F M 

Wedge-billed Woodcreeper 

Glyphorynchus 

spirurus 

F C M 


Amazonian Barred 

Woodcreeper 

Dendrocolaptes certhia S S M 

Strong-billed Woodcreeper 

Xiphocolaptes 

promeropirhynchus 

S S M 

Chestnut-rumped 

Woodcreeper 

Xiphorhynchus 

pardalotus 

C 

Straight-billed Woodcreeper Xiphorhynchus picus 

Buff-throated Woodcreeper 

Xiphorhynchus 

guttatus 

S U M 

Curve-billed Scythebill 

Campylorhamphus 

procurvoides 

U 

Typical Antbirds Thamnophilidae 

Fasciated Antshrike Cymbilaimus lineatus S F M 

Black-throated Antshrike Frederikena viridis U M 

Great Antshrike Taraba major S V 

Mouse-colored Antshrike Thamnophilus murinus U F M 

Guianan Slaty-Antshrike 

Thamnophilus 

punctatus 

U 

Spot-winged Antshrike Pygiptila stellaris U 

Dusky-throated Antshrike 

Thamnomanes 

ardesiacus 

F 

Cinereous Antshrike Thamnomanes caesius S F M 

Pygmy Antwren 

Myrmotherula 

brachyura 

S F V 

Guianan Streaked Antwren 


surinamensis 

C C V 

Rufous-bellied Antwren Myrmotherula guttata U U M 

Brown-bellied Antwren 


gutturalis 

S U M 

Grey Antwren 


menetriesii 

S M 

Long-winged Antwren 


longipennis 

U C M 

Spot-tailed Antwren 

Herpsilochmus 

sticturus 

F F M 

Todd’s Antwren 

Herpsilochmus 

stictocephalus 

F F V 

Dot-winged Antwren Microrhopias quixensis S 

Ash-winged Antwren Terenura spodioptila S 

Grey Antbird 

Cercomacra 

cinerascens 

U C M 

Dusky Antbird Cercomacra tyrannina U F M 

White-browed Antbird 

Myrmoborus 

myotherinus 

U M 

Warbling Antbird Hypocnemis cantator F F M 

Black-chinned Antbird 

Hypocnemoides 

melanopogon 

U F V 

Black-headed Antbird Percnostola rufifrons F F S,V 

Scale-backed Antbird Hylophylax poecilinota S F M 

Spot-backed Antbird Hylophylax naevia S F V,M 

Ferruginous-backed Antbird Myrmeciza ferruginea S M 

Wing-banded Antbird Myrmornis torquata S U M 

White-plumed Antbird Pithys albifrons S F M 

Rufous-throated Antbird Gymnopithys rufigula S F M 

Silvered Antbird Sclateria naevia S M 

Ground Antbirds Formicariidae 

Black-faced Antthrush Formicarius analis U U S,V 


Rufous-capped Antthrush Formicarius colma S M 

Spotted Antpitta Hylopezus macularius U F V 

Thrush-like Antpitta 

Myrmothera 

campanisona 

F F V 

Variegated Antpitta Grallaria varia S V,M 

Gnateaters Conopophagidae 

Chestnut-belted Gnateater Conopophaga aurita U 

Tyrant Flycatchers Tyrannidae 

Yellow-crowned Tyrannulet Tyrannulus elatus F 

Forest Elaenia Myiopagis gaimardii F U V,M 

McConnell’s Flycatcher Mionectes macconnelli U 

Piratic Flycatcher Legatus leucophaius S S 

Ochre-bellied Flycatcher Mionectes oleagineus S U M 

Short-crested Flycatcher Miarchus ferox S S,V 

Long-tailed Tyrant Colonia colonus S S 

Drab Water Tyrant Ochthornis littoralis F S 

Slender-footed Tyrannulet Zimmerius gracilipes S 

Double-banded Pygmy-Tyrant Lophotriccus vitiosus F 

Helmeted Pygmy-Tyrant Lophotriccus galeatus U U V 

Short-tailed Pygmy-Tyrant Myiornis ecuadatus F V 

Painted Tody-Flycatcher Todirostrum pictum U 

Common Tody-Flycatcher Todirostrum cinereum S V 

Ringed Antpipit Corythopis torquata U 

Yellow-margined Flycatcher Tolmomyias assimilis F 

Golden-crowned Spadebill Platyrinchus coronatus F F M 

White-crested Spadebill 

Platyrinchus 

platyrhynchos 

S 

Cinnamon-crested Spadebill Platyrinchus saturatus S 

Royal Flycatcher 

Onychorhynchus 

coronatus 

U 

Sulphur-rumped Flycatcher Myiobius barbatus U 

Bright-rumped Attila Attila spadiceus S U V 

Cinnamon Attila Attila cinnamomeus S V 

Grayish Mourner Rhytipterna simplex U 

Dusky-chested Flycatcher 

Myiozetetes 

luteiventris 

U 

Rusty-margined Flycatcher 

Myiozetetes 

cayanensis 

F S 

Yellow-throated Flycatcher Conopias parva U F S 

Tropical Kingbird 

Tyrannus 

melancholicus 

F U S 

Lesser Kiskadee Pitangus lictor U S 

Thrush-like Schiffornis Schiffornis turdinus S F S 

Screaming Piha Lipaugus vociferans C F S,V 

Cinereous Mourner Laniocera hypopyrra U 

Black-capped Becard 

Pachyramphus 

marginatus 

U 

Pink-throated Becard Pachyramphus minor S 

Cotingas Cotingidae 

Pompadour Cotinga Xipholena punicea S S S 


Capuchinbird 

Perissocephalus 

tricolor 

S U S,V 

Guianan Red Cotinga Phoenicircus carnifex S S 

Spangled Cotinga Cotinga cayana S S 

Purple-throated Fruitcrow Querula purpurata S S 

Tityras Tityridae 

Black-tailed Tityra Tityra cayana S S 

Dusky Purpletuft ? Iodopleura fusca S S 

Manakins Pipridae 

White-crowned Manakin Pipra pipra S F M 

Golden-headed Manakin Pipra erythrocephala F 

Tiny Tyrant-Manakin Tyranneutes virescens U U S,V 

White-bearded Manakin Manacus manacus S S,V 

Vireos Vireonidae 

Red-eyed Vireo Vireo olivaceus 

Buff-cheeked Greenlet 

Hylophilus 

muscicapinus 

F 

Tawny-crowned Greenlet 

Hylophilus 

ochraceiceps 

Rufous-browed Peppershrike Cyclarhis gujanensis U S, V 

Slatey-capped Shrike-Vireo Vireolaneus leucotis U S, V 

Swallows Hirundinidae 

White-winged Swallow Tachycineta albiventer C F S 

White-banded Swallow Atticora fasciata C C S 

Grey-breasted martin Progne chalybea S S 

Wrens Troglodytidae 

White-breasted Wood-Wren Henicorhina leucosticta S 

Coraya Wren Thryothorus coraya U U S,V 

Buff-breasted Wren Thryothorus leucotis F U S,V 

Wing-banded Wren Microcerculus bambla S 

Musician Wren Cyphorhinus arada S S V 

Gnatwrens, Gnatcatchers Sylviidae 

Long-billed Gnatwren 

Ramphocaenus 

melanurus 

S 

Thrushes Turdidae 

White-necked Thrush Turdus albicollis U 

Cocoa Thrush Turdus fumigatus S V 

Wood Warblers Parulidae 

River Warbler Phaeothlypis rivularis S 

Bananaquits Coerebidae 

Bananaquit Coereba flaveola S U S 

Tanagers Thraupidae 

Fulvous Shrike-Tanager Lanio fulvus ? 

Fulvous-crested Tanager 

Tachyphonus 

surinamus 

U 

Hepatic Tanager Piranga flava 

Silver-beaked Tanager Ramphocelus carbo F U S 

Blue-gray Tanager Thraupis episcopus 

Turquoise Tanager Tangara mexicana S U S 


Opal-rumped Tanager Tangara velia S S 

Blue Dacnis Dacnis cayana S 

Swallow Tanager Tersina viridis U S 

Emberizine Finches Emberizinae 

Red-capped Cardinal Paroaria gularis U 

Grosbeaks, Saltators Cardinalinae 

Slate-colored Grosbeak Pitylus grossus U F S, V 

Greyish Saltator Saltator coerulescens S S V 

Yellow-green Grosbeak 

Caryothraustes 

canadensis 

F 

Blue-black Grosbeak 

Cyanocompsa 

cyanoides 

S U S, V 

Finches Fringilidae 

Violaceous Euphonia Euphonia violacea S S 

New World Blackbirds Icteridae 

Giant Cowbird Scaphidura oryzivora F S 

Shiny Cowbird Molothrus bonariensis U S 

Yellow-rumped Cacique Cacicus cela C U S,V 

Red-rumped Cacique Cacicus haemorrhous C S,V 

Crested Oropendola 

Psarocolius 

decumanus 

C U S,V 

Green Oropendola Psarocolius viridis U U S,V 


ap p e n d i x iii 

Reptilian Diversity 

In the table the evidence is described as S sighting, V vocalisation or I indirect evidence 

such as footprints, scats or burrows. 

English Name Scientific Name ZSL Expedition 2009 Evidence 

Boas Boidae 

Green Anaconda Eunectes murinus S 

Amazon Tree Boa Corrallus hortulanus S 

Colubrids Colubridae 

Red Fire Snake Chironius scurrulus S 

Green Parrot Snake Lephtophis ahaetulla S 

Iguanas Iguanidae 

Hump-headed Iguana Urascodon superciliosus S 

Green Iguana Iguana iguana S 

Neotropical Ground Lizards Tropiduridae 

Collared Tree Lizard Plica plica S 

Whiptail Lizards Teiidae 

Jungle Runner Ameiva ameiva S 

Gold Tegu Tupinambis teguixin S,I 

Aligators and Caimans Alligatoridae 

Schneider’s Dwarf Caiman Palaeosuchus trigonatus S 

Tortoises Testudinidae 

Yellow-footed Tortoise Geochelone denticulata S 


ap p e n d i x iv 

EPA permission to conduct biodiversity research

Biodiversity of the Rewa Head B Zoological Society of London ...

Create successful ePaper yourself

Delete template?

Save as template?