Feather growth rate increases with latitude in four species of widespread resident Neotropical birds

Abstract

ABSTRACT The pace of life history events varies with latitude in many taxa. In birds, especially, life history events tend to be protracted in the tropics. This pattern is likely the result of reduced seasonality in resources and changes in trade-offs associated with risk of mortality. In general, animals invest more in reproduction per attempt and less in adult survival at higher latitudes. Feather growth is a major investment that birds make in their own survival, but geographic patterns of feather growth have received very little study. Evidence from separate studies of molt timing in individual species suggests that high-latitude species complete molt faster than tropical birds. Within species, feathers that are grown more quickly tend to show lower structural integrity than feathers grown more slowly, but seasonality of resources may place temporal constraints on the pace of feather growth. I hypothesized that increased seasonality of resources or decreased investment in adult survival in relation to...