Shorebird migration in western Kentucky: phenology, habitat use, and possible effects of prey availability

Staging areas along the coasts provide reliable food resources and shorebirds may use the same stopover locations every year. However, shorebirds use sites opportunistically in the interior of North America due to the transient nature of many habitats. Little is known, however, about the use of wetlands by migrating shorebirds in Kentucky. During 2004 and 2005, I examined the phenology of migration and habitat use of shorebirds using stopover habitats in Kentucky, and also examined possible relationships between prey availability and habitat selection by migrating shorebirds. To mitigate wetland loss, the Kentucky Department of Fish and Wildlife Resources (KDFWR) constructed four moist-soil units on Ballard, Sloughs, and Peabody Wildlife Management Areas (WMA) in western Kentucky. From March to October, I surveyed shorebirds at each moist soil unit as well as other natural and man-made wetlands at each WMA. Species abundance and foraging habitats were recorded a minimum of once per 10-day period. I also measured microhabitat variables (i.e., detritus depth and cover) and sampled macroinvertebrate populations throughout migration. Twenty-five species and 12,307 individual shorebirds were observed at the three wildlife management areas during my study, with Killdeer (Charadrius vociferous; N = 4134), Pectoral Sandpipers (Calidris melanotos; N= 2912), Least Sandpipers (Calidris minutilla; N = 1138), Greater Yellowlegs (Tringa melanoleuca; N = 942), and Lesser Yellowlegs (Tringa flavipes; N = 911) being most abundant. I recorded more individuals and species at Ballard WMA (the western-most site) than at Sloughs and Peabody WMAs. Wet mud was the most commonly used foraging microhabitat by shorebirds (2832 of 11936 observations, or 23.7%), and the presence of shallow water best discriminated between sites where shorebirds were observed foraging and randomly selected, apparently unused sites. Although used by shorebirds in my study, such habitat was not always available during migration at the units designed for use by shorebirds. Because both natural and managed wetlands provide stopover sites for shorebirds during spring and fall migration in Kentucky and, given that populations of many species are declining, it is important that wetlands be preserved and better managed and that additional habitat be created