Red Knot Calidris canutus roselaari migration connectivity, abundance and non-breeding distribution along the Pacific coast of the Americas
168 – 180
1 December 13
Roberto Carmona, Nallely Arce, Victor Ayala-Perez, Adrianna Hernández-Alvarez, Joseph B. Buchanan, Lori J. Salzer, Pavel S. Tomkovich, James A. Johnson, Robert E. Gill, Brian J. McCaffery, James E. Lyons, Larry J. Niles, David Newstead
Marine Biology Department, Universidad Autónoma de Baja California Sur, Apartado postal 19-B, La Paz, Baja California Sur, CP 23000 Mexico
Red Knots Calidris canutus roselaari occur along the Pacific coast of the Americas and may use as few as four stopover or staging sites during spring migration. There are key information gaps regarding this population’s status and non-breeding distribution because of its localized distribution during migration, relatively small population size (estimated population of 17,000) and a poor understanding of the location of major overwintering sites. Based on resightings of marked birds, we assessed migratory connectivity of Red Knots along the Pacific coast. Knots captured and marked at two sites in NW Mexico have been observed at several locations, including migration areas in coastal Washington and the Yukon-Kuskokwim Delta in W Alaska and breeding areas in NW Alaska. The greatest connectivity was between Guerrero Negro/Ojo de Liebre and Golfo de Santa Clara, Mexico, and during northbound migration, between those two sites and coastal Washington, USA. Much less is known about the southbound migration; comparatively few marked knots have been resighted north of Mexico during autumn. We reviewed scientific literature and consulted eBird data to compile observational records of Red Knots along the Pacific coast. Records from mainland NW Mexico document substantial aggregations (hundreds or thousands) of Red Knots at several locations during the non-breeding season. Connectivity involving locations in mainland NW Mexico may be demonstrated with more field effort. Additional records along the Pacific coast south of Mexico, which involved far fewer birds, extended to extreme southern Chile near the documented winter range of the rufa subspecies. The available information suggests the possibility of an area of overlap in the non-breeding range of roselaari and rufa in southern Mexico; the southernmost distribution of roselaari remains incompletely known. Comprehensive conservation assessments will require additional investigation to identify important stopover and overwintering sites.