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Abstract(s)
Seabirds have the potential to be used as indicators
for monitoring changes in the southern oceans.
However, many species and populations are still poorly
known. The thin-billed prion (Pachyptila belcheri) is the
most abundant seabird species around the Falkland
Islands, but this far, no detailed censuses of its populations
had been carried out. In this study, we developed
a methodology, based on standard field methods
combined with a Geographical Information System, to
census the biggest known colony (New Island) of this
species. Data were also collected on nesting habitat
preferences. Results indicate that there are 1,081,000
(95% confidence limits: 815,000–1,346,000) apparently
active nest-burrow entrances on New Island South
which, given the very high occupancy rates by known
breeders, should correspond to a similar number of
nesting couples. We present quantitative evidence that this result can be extrapolated for the entire island,
giving an overall estimate of 2 million pairs. Prions have
an almost ubiquitous distribution on New Island, but
they are more frequent in areas with steeper slopes (excluding
cliffs). Habitats dominated by introduced grass
species generally hold higher densities of nests in comparison
to most native formations.
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Citation
Polar Biology, 26, 202-207