Authors: Brian C. Weeks, David E.Willard, Marketa Zimova, Aspen A. Ellis, Max L. Witynski, Mary Hennen and Benjamin M. Winger
Publication: Ecology Letters
Publication Link: https://publons.com/publon/10.1111/ele.13434/
Keywords: Allometry, body size, climate change, migration, morphology
Abstract: Increasing temperatures associated with climate change are predicted to cause reductions in body size, a key determinant of animal physiology and ecology. Using a four-decade specimen series of 70 716 individuals of 52 North American migratory bird species, we demonstrate that increasing
annual summer temperature over the 40-year period predicts consistent reductions in body size across these diverse taxa. Concurrently, wing length – an index of body shape that impacts numerous aspects of avian ecology and behaviour – has consistently increased across species. Our findings suggest that warming-induced body size reduction is a general response to climate change, and reveal a similarly consistent and unexpected shift in body shape. We hypothesise that increasing wing length represents a compensatory adaptation to maintain migration as reductions in body size have increased the metabolic cost of flight. An improved understanding of warming-induced morphological changes is important for predicting biotic responses to global change.