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San Francisco, CA, United States

Carter H.R.,Carter Biological Consulting | Ainley D.G.,983 University Avenue | Wolf S.G.,Center for Biological Diversity | Weinstein A.M.,California Audubon
Marine Ornithology

In February 2015, a special paper session about the range-wide conservation and science of the Ashy Storm-Petrel Oceanodroma homochroa (ASSP) was held at the Pacific Seabird Group annual meeting. The main goal was to share information amassed during the past 20 years on this species, which breeds almost entirely in California, United States, for formulating future research and conservation actions. One key result is the six papers on ASSP and two on Leach’s Storm-Petrels O. leucorhoa in this issue of Marine Ornithology. In this introduction, we augment contributed papers with a summary of historic and recent knowledge about the ASSP breeding range, key conservation issues and data gaps. The largest breeding concentration is at the South Farallon Islands in central California, but four other concentrations occur in southern California at the Channel Islands (Prince, Santa Barbara-Sutil, northwest Santa Cruz and northeast Santa Cruz). Over the past two centuries, many ASSP breeding colonies have been affected by introduced mammals and human-altered breeding habitats. Population decline due to heavy avian predation has been documented at the South Farallon Islands since 1972; decline due to eggshell thinning from organochlorine pollutants is suspected in the Channel Islands since the 1950s. Eradication of introduced mammals, reduction of pollution and social attraction (vocalization broadcasting and artificial nest sites) have helped to restore population size at certain colonies. © 2016, Marine Ornithology. All rights reserved. Source

Becker B.H.,Pacific Coast Science and Learning Center | Carter H.R.,California Institute of Environmental Studies | Carter H.R.,Humboldt State University | Henderson R.P.,California Institute of Environmental Studies | And 3 more authors.
Marine Ornithology

While the largest Ashy Storm-Petrel Oceanodroma homochroa (ASSP) colonies are at offshore islands, small colonies also occur along the mainland coast of northern and central California. We describe past and current monitoring efforts along the coastline of Point Reyes National Seashore, California. From 2012 to 2015, we conducted nest searches and mist netting in late August or early September at the Bird Rock and Stormy Stack colonies, as well as the Point Reyes Headlands. Potential nest sites on Stormy Stack (~17) and Bird Rock (~40) included 4-7 and 3-6 active nests, respectively. These nest numbers were similar to those from past complete surveys at Bird Rock in 1989 and Stormy Stack in 2001, suggesting little change in colony size over time. Birds per capture hour during single nights of mist-netting at Bird Rock in 2012 (1.46) and 2013 (1.44) were lower than on two nights in 1989 (5.47 and 3.08), leading to a higher estimate of 37 pairs in 1989. Two ASSP were also netted at the Point Reyes Headlands in 2013, but no nests were found during limited searches in 2013 and 2015. Standardized long-term monitoring of nests at Bird Rock and Stormy Stack will provide better information on future population trends and conservation issues. © 2016, Marine Ornithology. All rights reserved. Source

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