Linking winter and summer events in a migratory bird by using stable-carbon isotopes
For migratory birds, early arrival and physical condition on the breeding grounds are important determinants of reproductive success and fitness. Differences in arrival times often exceed a month, and later arriving individuals are often in poorer condition. Habitat-specific isotopic signatures indicate that the quality of winter habitats occupied by American redstarts (Setophaga ruticilla) determines their physical condition and spring departure dates, which in turn result in variable arrival schedules and condition on temperate breeding grounds. These findings link events in tropical winter grounds with those in temperate breeding areas for a migratory songbird and provide evidence that winter habitats may be limiting.
Marra
PP
P. P. Marra and R. T. Holmes, Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA. K. A. Hobson, Prairie and Northern Wildlife Research Center, Canadian Wildlife Service, Saskatoon, S7NOX4 SK, Canada.
Hobson
KA
Holmes
RT