Carmona R.,Autonomous University of Baja California Sur |
Arce N.,Autonomous University of Baja California Sur |
Ayala-Perez V.,Autonomous University of Baja California Sur |
Hernandez-Alvarez A.,Autonomous University of Baja California Sur |
And 9 more authors.
Wader Study Group Bulletin | Year: 2013
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. © 2013, International Wader Study Group. All rights reserved.
Newstead D.J.,1305 N Shoreline Blvd |
Niles L.J.,Conserve Wildlife Foundation of New Jersey |
Porter R.R.,800 Quinard Court |
Dey A.D.,Fish and Wildlife |
And 2 more authors.
Wader Study Group Bulletin | Year: 2013
Red Knots Calidris canutus are commonly observed along the Texas coast during fall and spring. Although some significant winter records have been reported in Texas, it was previously unknown if birds were using Texas as a wintering area or primarily as a stopover area en route to more southerly wintering destinations. We fitted 69 Red Knots with geolocators on Mustang and Padre Islands between fall 2009 and fall 2010, and recovered eight of them between fall 2010 and spring 2012. The data showed that these knots: 1) spent nearly the entire nonbreeding phase of their annual cycle (78.4%) in the north-west Gulf of Mexico, 2) used the Mid- Continent (or Central) Flyway as a migratory route on both north and southbound migrations, 3) used stopover sites in the Northern Great Plains of the United States and Canada as well as the Nelson River Delta/Hudson Bay area, and 4) exhibited stronger consistency in timing of northbound migratory movements than in southbound movements. For the two birds for which geolocator data included consecutive years of data, one showed consistency in northbound and southbound stopover location between years, while the other showed variability in northbound, but not southbound stopover locations. A geolocator recovered from a bird that was originally captured in the year in which it hatched showed that it also oversummered in Texas. The data further highlights the critical importance of the north-west Gulf of Mexico – particularly the Laguna Madre and Padre Island – for this population of Red Knots, and the need for further investigation to discover specific wintering sites. © 2013, International Wader Study Group. All rights reserved.