Recovery of a threatened seabird after eradication of an introduced predator: eight years of progress for Scripps’s murrelet at Anacapa Island, California

Published source details Whitworth D.L., Carter H.R. & Gress F. (2013) Recovery of a threatened seabird after eradication of an introduced predator: eight years of progress for Scripps’s murrelet at Anacapa Island, California. Biological Conservation, 162, 52-59.
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Summary

Control mammalian predators on islands for seabirds

A before–and–after study in 2001–2010 on Anacapa Island, California, USA (Whitworth et al. 2013) found that after eradication of the invasive black rat Rattus rattus, the breeding success of Scripps’s murrelets Synthliboramphus scrippsi increased threefold, mainly due to the reduction in egg predation, and murrelets expanded their breeding habitat. After rat eradication, there were increases in the number of occupied nests (before: 10; after: 44) and sea-cave hatching success (before: 30%: after: 85%). Outside sea caves hatching success was comparable (80%) but there was no comparison data before eradication. Post-eradication, the number of occupied nests increased annually by 10% in sea caves and 24% outside sea caves. Rat eradication was phased in December 2001 and November 2002. During the poisoning campaign, endemic mice were taken into captivity and later released back on Anacapa. Due to rat predation, murellets were breeding only in sea caves and pre–eradication monitoring was conducted at ten shoreline sea caves, weekly in 2001–2004 to every 10–17 days in 2005–2010. Post–eradication, additional areas were surveyed, outside sea caves.