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Patterns And Mechanisms Of Heterogeneous Breeding Distribution Shifts Of North American Migratory Birds, Hanna M. Mccaslin, Julie A. Heath

Biology Faculty Publications and Presentations

There is widespread evidence that species distributions are shifting in response to climate change. Warming temperatures and climate niche constraints are hypothesized drivers of northward shifts in temperate migratory bird breeding distributions, but heterogeneity in the direction of distribution shifts suggests that the climate niche hypothesis does not explain all changes in distributions. We propose that: 1) changes in migration costs and benefits related to dampened seasonal differences between breeding and winter areas, 2) sensitivity to supplemental cues that affect duration of migration and onset of reproduction, 3) a latitudinal mismatch-driven fitness gradient, or a combination of these drivers may …