Genetic analysis of museum samples suggests temporal stability in the Mexican nonbreeding distribution of a neotropical migrant

Abstract

Seasonal migration is highly labile from an evolutionary perspective and known to rapidly evolve in response to selective pressures. However, long-distance migratory birds rely partially on innate genetic programs and may be constrained in their ability to alter their migratory behavior. We take advantage of recent advances in our ability to genotype historical DNA samples to examine the temporal stability of migratory connections between breeding and nonbreeding populations (i.e. migratory connectivity) and population-level nonbreeding distributions in the Wilson's warbler Cardellina pusilla, a long-distance migratory songbird. By assigning historical and contemporary samples collected across the nonbreeding range to genetically distinct breeding clusters, we suggest that broad-scale population-level nonbreeding distributions within this species have remained largely consistent within Mexico from the mid-1900s to the present day. These findings support the idea that the nonbreeding distributions of long-distance migrants may remain stable over long time scales, even in the face of rapid environmental change.