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112 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
with diverse taphonomic origins to offset the biases inherent in
any one depositional environment. For example, pitfalls overly
represent ground-dwelling species, and small, volant passerines
are rare. The chronology of sites is based on 99 new and
27 preexisting radiocarbon dates obtained from bones (Worthy,
1993a, 1997; Worthy and Holdaway, 1993, 1994a, 1995,
1996). Most dates are based on accelerator-mass-spectrometry
analysis of collagen or gelatin extractions from single bones as
detailed in Worthy (1993a, 1997) and Worthy and Holdaway
(1993, 1994a, 1995, 1996). Geologic ages cited hereafter are
conventional radiocarbon ages. Nomenclature for species' binomials
and English names of modern birds follows Turbott
(1990).
ACKNOWLEDGMENTS.—This work was supported by a grant
from the New Zealand Foundation for Research, Science, and
Technology, and with funds from the New Zealand Lottery
Grants Board for some of the radiocarbon dates. The generous
support of the Museum of New Zealand Te Papa Tongarewa,
Canterbury Museum, and Otago Museum, and their curators, is
gratefully acknowledged. Much of the initial work for this
study was done with Richard Holdaway, with whom numerous
discussions have enabled the development of ideas contained
herein. Lastly, the work would not have been possible without
the support of the many land owners and the Department of
Conservation permitting access to fossil sites. A critical review
by Storrs Olson led to a greatly improved text.
The Study Areas
GEOLOGY AND CLIMATE
FIGURE 1
WEST COAST.—The lowland (0-300 m) karst region between
Punakaiki in the south and Charleston to the north, on
the west coast of South Island, was studied by Worthy and
Holdaway (1993). The area has a mild, humid climate, with
mean monthly temperatures of 10°-18° C, and 2800-4000 mm
of rainfall annually. A tall, closed-canopy, mixed beech
{Nothofagus)/podocavp (dominated by Dacrydium cupressinum
Lambert) rainforest characterizes the unmodified vegetation.
The fossil faunas are from sites in 42 caves and are up to
25,000 years old. Most faunas are from pitfalls. Some sites
contained single skeletons lying on the surface; their origin is
attributed to "vagrants" (individuals that entered the cave for
any number of reasons and that often traveled 10-100 m from
the entrance before dying). Often vagrants entered via large,
horizontal entrances. The age of all such skeletons was considered
individually because adjacent skeletons varied in age by
thousands of years and may have been deposited during either
the last glacial period or the present interglacial. There was
only one fauna accumulated by the predatory Laughing Owl
{Sceloglaux albifacies) (Worthy and Holdaway, 1994b).
HONEYCOMB HILL CAVE SYSTEM.—This cave system lies
inland of Karamea, in the northwest part of South Island, in a
valley at an altitude of about 300 m that receives 3000-4000
mm of rainfall annually. The present vegetation and temperatures
are similar to those of the west-coast study area, although
winter frosts occur.
There are more than 50 discrete fossil sites in this complex
cave, which has about 14 km of passages and 70 entrances. The
Graveyard and the Eagles Roost are the two most important
sites (Worthy, 1993a). The fossil deposits are up to 20,000
years old.
TAKAKA HILL AND TAKAKA VALLEY.—Takaka Hill and
Takaka Valley are in the northern part of South Island. Because
southwesterly airflows prevail over New Zealand, and Takaka
is east of a tract of mountains, it receives considerably less
rainfall than the two previous study areas, about 2000-2500
mm annually. Temperatures are similar to those of the western
sites (mean annual temperature for Takaka Valley is 12.7° C),
although there is greater seasonality, with summer drought
common, and on Takaka Hill snowfalls can be expected during
winter. Sites in the valley (0-200 m) were compared to hill faunas
(600-800 m) to detect altitudinal effects. The late Holocene
vegetation of the valley was a tall, multitiered, closed-canopy
mixed podocarp (dominated by Podocarpus totara D. Don)
and broadleaf forest, compared with a closed-canopy (10-15
m), primarily beech {Nothofagus spp.) forest, with some Hall's
Totara {Podocarpus hallii Kirk) and cedar {Libocedrus spp.) on
the hill.
Fossil faunas were obtained from 43 caves in the combined
hill and valley areas (Worthy and Holdaway, 1994a), although
most were from the more extensive karst areas on the hill. Deposits
are up to 30,000 years old and are mainly pitfalls, with
only two significant faunas from Laughing Owl prey accumulations.
None are in alluvial contexts.
NORTH CANTERBURY-MT. COOKSON.—The Mt. Cookson
study area is a karst plateau at 400-600 m in the province of
North Canterbury. Because it lies just east of the high Amuri
Range and is about 20 km from the east coast, there is a marked
rain-shadow effect. It has an annual rainfall of about 700 mm
and a markedly seasonal climate; summers are hot (temperatures
often >30° C), with drought common, and in winter snow
lies on the ground for several weeks. The late Holocene vegetation
was a closed-canopy beech forest.
Fossil faunas were from several pitfall sites and from three
deposits accumulated by falcons {Falco novaeseelandiae)
(Worthy and Holdaway, 1995). The sites are up to 38,000 years
old.
NORTH CANTERBURY-WAIKARL—All sites in the Waikari
study area are at an altitude of 200-400 m and are within 10
km of Waikari in North Canterbury. The climate is dry, with
annual rainfall of about 660 mm, and warm, with a mean annual
temperature of 10.8° C. It is markedly seasonal; summer
droughts are common, and in winter frosts and occasional
snowfalls are normal. The late Holocene vegetation
(5000-1000 years ago) was a tall podocarp (dominated by
Prumnopitys taxifolia (Banks & Solander ex Lamb.) de
Laub.) forest on the valley floors, with beech forest above this
on the higher slopes (to 800 m). Areas of shrublands and
grasslands were present on ridges and along river beds. The