Tuesday, May 30, 2017

Recent increase in population size of red-billed gulls (Larus novaehollandiae scopulinus) at Otago, southern New Zealand

TitleRecent increase in population size of red-billed gulls (Larus novaehollandiae scopulinus) at Otago, southern New Zealand
Publication TypeJournal Article
Year of Publication2012
AuthorsPerriman, L, Lalas, C
JournalNotornis
Volume59
Issue3&4
Pagination138-147
Type of ArticleArticle
Keywordsconservation management, Larus novaehollandiae scopulinus, oceanography, Otago, population increase, red-billed gull
Abstract

The New Zealand endemic red-billed gull (Larus novaehollandiae scopulinus) was designated as a ‘Nationally Vulnerable’ species in 2008 as a consequence of recent substantial population declines at large breeding colonies, particularly the one situated at Kaikoura, north-east South Island. In contrast, numbers increased further south along the Otago coastline, south-east South Island. Nest numbers from 7 surveys from Moeraki to Nugget Point increased from 565–1480 in 1992 to 4612–4652 in 2011 and corresponded to an average annual increase of 6–10% through 20 years. The recent decline at Kaikoura has been attributed mainly to a decline in prey availability linked to changes in oceanographic indicators, including sea surface temperature (SST). Fluctuations in SST at Otago and Kaikoura are negatively correlated and may explain the concomitant opposite trends in population sizes. Conservation management at Taiaroa Head and at other key mainland breeding locations is necessary to ensure the viability of red-billed gulls at Otago.

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