SAP: Chatham Island Shag
Chatham Island Shag

SAP: Chatham Island Shag

Worldwide Species Action Plans

Chatham Island ShagThis species is restricted to the Chatham Islands, New Zealand. Three islands support breeding: Chatham, Star Keys and Rabbit, with a further population on North East Reef. In 1997, a census found a total of 842 pairs at 10 sites, with the largest colony on Star Keys which, in 1980, had 358 nests containing eggs or chicks. However, surveys in 2003-2004 estimated the breeding population to be 271 pairs, distributed at 13 colonies, with the largest colony on Star Keys holding 81 pairs. This represents a 67.8% decrease in total breeding pairs since 1997, but a poor breeding season or variability in the timing of breeding within and between seasons may have contributed to this apparent decrease, and further surveys are needed to confirm population trends. Although colonies are spread over three islands, the species’s breeding range totals less than 1 ha. Feeding range is assumed to be 24 km (cf. New Zealand King Shag P. carunculatus). Surveys in 1997 found 840 pairs, but in 2003 only 270 pairs were counted, a 68% decline in six years. A partial survey in 2007/2008 reported a 30% increase on 2003 numbers (S. Waugh in litt. 2009). As such, a cautious estimate places the percentage decline over three generations as 30-49%. However, it is possible that the low numbers in 2003 may reflect a poor breeding season or variability in the timing of breeding between seasons, and further surveys are needed to confirm population trends (R. Hitchmough in litt. 2005). A proposed complete survey in 2009 was cancelled due to budget cuts

 

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