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Feather growth rate and mass in nearctic passerines with variablemigratory behavior and molt pattern

De la Hera, I. and DeSante, D.F. and Mila, B. (2012) Feather growth rate and mass in nearctic passerines with variablemigratory behavior and molt pattern. The Auk, 129, 222-230. ISSN 0004-8038.

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Bird species vary greatly in the duration of their annual complete feather molt. However, such variation is not well documented in birds from many biogeographic areas, which restricts our understanding of the diversification of molt strategies. Recent research has revealed that molt duration can be estimated in passerines from ptilochronology-based measurements of the growth rate of their tail feathers. We used this approach to explore how molt duration varied in 98 Nearctic species that have different migratory strategies and molt patterns. As previously documented for Palearctic species, migration was associated with a shortening of molt duration among species that molted during summer on their breeding range. However, molts of winter-molting migratory species were as long as those of summer-molting sedentary species, which suggests that winter molt also allows Nearctic migrants to avoid the temporal constraints experienced during summer. Our results also suggest that migratory species that undergo a stopover molt within the Mexican monsoon region have the shortest molt duration among all Nearctic passerines. Interestingly, and contrary to expectations from a potential tradeoff between molt duration and feather quality, observed variation in feather growth rate was positively correlated with differences in tail feather mass, which may be caused by differences among groups in the availability of resources for molting. We encourage the use of similar approaches to study the variation in molt duration in other geographic areas where knowledge of the evolution of molt is limited.

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:12369
Deposited On:13 Jun 2012 02:00
Last Modified:15 Jan 2014 09:30

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