Estimating Origins of Short-Distance Migrant Songbirds in North America: Contrasting Inferences From Hydrogen Isotope Measurements of Feathers, Claws, and Blood

Mesoscale patterns of altitudinal tenancy in migratory wood warblers inferred from stable carbon isotopes

“…The validity of such studies depends on the isotope turnover rates of assayed tissues and the duration of migration. Feeding experiments indicate that isotopic turnover rates in whole blood and plasma of small migratory birds (,20 g) are rapid, perhaps too rapid to provide much isotopic signal of wintering habitat for species sampled on breeding territories at high latitudes (Hobson and Bairlein 2003, Pearson et al 2003, Hobson 2005a, Mazerolle and Hobson 2005. NearcticNeotropical migratory passerines, such as the Blackthroated Blue Warbler, typically take several weeks to reach their breeding grounds (Cooke 1888(Cooke , 1915.…”

“…This implies that tissues with high metabolic rates sampled from migratory species on breeding territories have limited value as isotopic proxies of wintering habitat use. Tissues that lock in isotopic signals over a limited time frame such as toenail keratins and feathers, for species that molt on the wintering grounds, are much more likely to reflect the isotopic composition of wintering-ground diet and habitats (Chamberlain et al 2000, Bearhop et al 2004, Mazerolle and Hobson 2005. …”

Assessing population structure and migratory patterns of White-throated Sparrow (Zonotrichia albicollis) breeding populations in western Canada.

“…Mountains (Campbell et al 2001;Mazerolle and Hobson 2007), but a population located in the Central Interior of British Columbia (west from the Rockies), that is not included in most species breeding range maps also exists (e.g., Sibley 2000). The genetic relationship of the Central Interior population to those breeding east of the Rockies is unknown; however, preliminary data of song structure indicates some degree of differentiation (unpublished data, Mesias, V., Otter, K., Mora, M., Ramsay, S., and Murray, B.).…”

“…Mountains (Campbell et al 2001;Mazerolle and Hobson 2007 Knapton et al 1984). Even though one of the two morphs has been reported to be in higher proportion in some populations, overall both morphs are equally represented through the entire breeding range (Falls and Kopachena 2010).…”

“…Each technique has its own pros and cons (Coiffait et al 2009); however, none of them has been shown to be powerful enough to answer all the questions about bird migration. For this reason, several studies have used different combinations of techniques to understand migratory connectivity (e.g., Boulet and Gibbs 2006;Clegg et al 2003;Mazerolle and Hobson 2007;Norris et al 2006).…”