Point Blue Conservation Science

About: Point Blue Conservation Science is a nonprofit organization based out in Petaluma, California, United States. It is known for research contribution in the topics: Population & Foraging. The organization has 151 authors who have published 330 publications receiving 11929 citations. The organization is also known as: Point Reyes Bird Observatory.

The distribution and status of Worthen's Sparrow Spizella wortheni : a review

Abstract: Originally described last century from New Mexico, U.S.A., Worthen's Sparrow Spizella wortheni has subsequently been recorded from just eight states in Mexico centred on the interior of the north-east of the country. Records during the last 30 years originate from just Coahuila and Nuevo Leon, with those during the last 10 years exclusively from two small areas in south-eastern Coahuila and western Nuevo Leon: it appears that this poorly known species has been suffering a range contraction owing to the widespread destruction of its shrubby (mesquite or yucca-juniper) grassland habitat. Little detail is known of its specific requirements, local movements, or even its distribution, and it is proposed that Worthen's Sparrow be formally recognized as a threatened species.Originalmente descrito el siglo pasado a partir de ejemplares procedentes de Nuevo Mejico, U.S.A., Spizella wortheni ha sido posteriormente citado en ocho estados mejicanos, todos en el interior del noreste del pais. Durante los ultimos 30 anos, todas las citas provienen de Coahuila y Nuevo Leon, y durante los ultimos 10 exclusivamente de dos pequenas areas del sureste de Coahuila y del oeste de Nuevo Leon: parece que el area de distribution de esta escasamente conocida especie ha ido reduciendose debido a una generalizada destruction de su habitat de matorral (mescal o yuca-enebro) pastizal. Se conoce muy poco de sus requerimientos especificos, movimientos locales, o incluso su distribution, y se propone que Spizella wortheni sea formalmente reconocido como una especie amenazada.

Local and Landscape Habitat Associations of Shorebirds in Wetlands of the Sacramento Valley of California

Abstract: The Sacramento Valley of California is a site of international importance for shorebirds despite having lost >90% of its historic wetlands. Currently both managed wetlands and flooded agri...

Estimating effectiveness of speed reduction measures for decreasing whale-strike mortality in a high-risk region

Abstract: Recent estimates of blue (Balaenoptera musculus) and humpback (Megaptera novaeangliae) whale ship-strike deaths on the US west coast are above the Potential Biological Removal limit determined by the National Marine Fisheries Service. Beginning in 2015, the National Oceanographic and Atmospheric Administration requested voluntary Vessel Speed Reductions (VSR) in the designated shipping routes off San Francisco, California, USA, in order to decrease whale mortality from ship strikes. We applied a ship strike model based on whale density and Automatic Identification System (AIS) vessel data. We bootstrapped speeds from vessels that transited when no VSR was in place to assess the effect of the VSR on strike mortality rates. Finally, we calculated the expected mortality for hypothetical compliance scenarios by programmatically imposing speed caps. Average predicted mortality for the region was 2.7 blue whales and 7.0 humpback whales in a 4 month period. Compared to years prior to the VSR (2012−2014), vessel speeds during the VSR were slower. This lowered blue whale deaths within the shipping lanes by 11–13% and humpback whale deaths by 9–10% in 2016−2017. If 95% of mariners adhered to recommended 10 knot (kn) limits in the shipping lanes alone, we predicted twice as many blue whale and 3 times as many humpback whale deaths would be avoided relative to current adherence. Adding a 10 kn speed limit (with 95% coope ration) at the ends of each of the lanes would result in about 5and 4-fold reductions in blue whale and humpback whale mortality, respectively, relative to current practices. Our approach can evaluate ship strikes and mitigation measures for whale populations around the globe.

Migration patterns of San Francisco Bay AreaHermit Thrushes differ across a fine spatial scale

Abstract: Abstract Effective conservation of short-distance migrants requires an understanding of intraspecific variation in migratory patterns across small spatial scales. Until the advent of ultra-light geolocation devices, our knowledge of the migratory connectivity of songbirds was limited. For the Hermit Thrush (Catharus guttatus), subspecies delineations and connectivity patterns have been unclear in the portion of their breeding range in western North America from southeastern Alaska to northwestern Washington, where individuals wintering in the San Francisco Bay Area of California purportedly breed. To determine breeding locations and migratory timing of the Bay Area’s wintering Hermit Thrushes, we deployed geolocators at sites to the north and south of the San Francisco Bay. We compared results from these two regions to one another and to connectivity patterns suggested by subspecies definitions. We collected morphometrics to identify regional differences. Hermit Thrushes that wintered in the North Bay had a wider and more southerly breeding distribution from the British Columbia coast to northwestern Washington, whereas South Bay thrushes migrated to southeastern Alaska and the British Columbia coast. In general, North Bay thrushes departed wintering grounds and arrived on breeding grounds earlier than South Bay thrushes, but we cannot eliminate sex as a factor in these differences. Regional morphology differed only in bill length. Intraspecific isolation in glacial refugia during the Late Pleistocene may explain these fine-scale geographic variations in migration patterns and morphology.