2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
Each of five teams, which included 2-3 people (1-2 observers and 1 recorder), was responsible for
surveying an assigned set of zones over each survey day, which extended from approximately 0700 to
1200. Team size depended upon complexity of the survey area and seasonal abundance of birds.
Multiple observers allowed teams to minimize double-counts associated with bird movements between
zones.
The field biologists used both binoculars and spotting scopes to identify and count species. All teams
conducted surveys simultaneously. Data collected included species, number of individuals, activities of
the birds (foraging, flying, resting, or showing evidence of breeding), and habitats in which the birds
occurred (open water, nesting site, mud flat, salt marsh, disturbed salt marsh, freshwater marsh, willow
riparian, baccharis scrub, salt panne [dry], inundated salt panne, and non-native vegetation). Weather
conditions, including air temperature, wind speed, wind direction, cloud cover, precipitation, and tide
height, were recorded several times during each survey day.
Due to the large size of the zones being surveyed, particularly in the FTB, identifications were often
made over great distances. When it was not possible to identify a bird to the species level due to
distance, overhead flight, or a limited view of the bird, a less specific identification was made such as
unidentified gull or unidentified swallow. In cases where challenging lighting conditions and long
distances prevented the distinction between two species that are very similar and require close
inspection to identify, the less specific name was used if necessary, i.e. greater and lesser scaup or
long-billed and short-billed dowitchers were identified as unidentified scaup and unidentified
dowitchers.
The accuracy of the bird counts was compromised somewhat on Zones 70 and 71 (Nest Site 1) during
the June and August surveys. This was due to the large number of birds, including western snowy
plover, elegant tern (Thalasseus elegans), black skimmer (Rynchops niger), California least tern, royal
tern (Thalasseus maximus), and Caspian tern (Hydroprogne caspia), that were nesting and rearing their
young on Nest Site 1. To avoid disturbing the nesting birds, the survey of these zones was conducted
from either end of the nest site and therefore some avian species, particularly in the center of the site,
were likely missed.
Avifauna observed during field surveys were recorded on field data sheets along with collection
location, time, and name of field observer. All field staff carried a field guide to avoid
misidentification of uncommon species. In order to avoid double counts of birds, individuals that were
observed on the boundary of a zone or flying from one zone to another were recorded by only one
team. This was determined by communicating directly with the other team by radio or phone. If
contact could not be made, the data were recorded and details noted on the data sheets. At the end of
each survey, field staff reviewed the data sheets and, if necessary, corrections were made on the data
sheets to avoid over-counting of individual birds.
In some cases it was not possible to definitively assess whether a double-count had occurred,
particularly with large flocks of highly transitory shorebirds and with raptors, which ranged over all
survey zones and were seen on both survey days. In cases where an over-count is suspected, a note has
been made on the reported table of birds observed.
All survey data were initially recorded in the field on hard copy data sheets and then transferred in the
office to digital database files and checked for accuracy. The database was then queried to extract
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