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American Oystercatcher (Haematopus palliates) nest abundance and success on Isla Alcatraz

Project Description

Little is published on American Oystercatchers in the Gulf of California. It is estimated that the subspecies found in northwestern Mexico (H. p.frazari) has the smallest population of any of the Oystercatcher subspecies in North America (estimated to be 3,000 individuals in 2009). Starting in 2008, each season 4-10 nests have been found on Isla Alcatraz, and nesting success has been evaluated.

Project Results

In the spring of 2009, three of the five nests hatched young while the condition of one other nest was unknown. At least one nest was lost without hatching young, to either by predation or trampling by humans.In spring of 2010, eight nests were found, but only one nest had eggs for more than two consecutive weeks. One two-week old chick was observed. Due to the incubating time of this species and the lack of chicks on the island, it is assumed that only one nest was successful that year. The causes of failure for the other seven nests are unknown, but are likely related to predation by gulls, vultures, or ravens, and human presence on the island.

Reports & Publications

  1. Research and Conservation Program Report (2007-2011). Prescott College Kino Bay Center for Cultural and Ecological Studies 
  2. Reporte de proyectos de investigación en el Área de Protección deFlora y Fauna Islas del Golfo de California (2010-11). Centro de Estudios Culturales y Ecológicos Prescott College A. C., Bahía Kino, Sonora
  3. Reporte de proyectos de investigación en el Area de Proteccion de Flora y Fauna Islas del Golfo de California (2009-2010). Centro de Estudios Culturales y Ecológicos Prescott College A. C., Bahía Kino, Sonora