Evolution of moult-migration is directly linked to aridity of the breeding grounds in North American passerines

Pageau, Claudie, Thompson Rivers University, Thompson Rivers University, https://orcid.org/0000-0003-0371-5602

Tonra, Christopher, The Ohio State University

Shaikh, Mateen, Thompson Rivers University, Thompson Rivers University

Flood, Nancy, Thompson Rivers University

Reudink, Matthew, Thompson Rivers University

Tonra, Christopher M., Ohio Department of Natural Resources

Flood, Nancy J., Thompson Rivers University

Reudink, Matthew W., Thompson Rivers University

claudie.pageau@gmail.com

Publication date: June 15, 2021

Publisher: Dryad

https://doi.org/10.5061/dryad.vhhmgqnqq

Citation

Pageau, Claudie et al. (2021), Evolution of moult-migration is directly linked to aridity of the breeding grounds in North American passerines, Dryad, Dataset, https://doi.org/10.5061/dryad.vhhmgqnqq

Abstract

To avoid energy allocation conflicts, birds generally separate breeding, migration and moult during the annual cycle. North American passerines typically moult on the breeding grounds prior to autumn migration. However, some have evolved a moult-migration strategy in which they delay moult until stopping over during autumn migration. Rohwer et al . (2005) proposed the ‘push–pull hypothesis' as an explanation for the evolution of this moult strategy, but it has not been empirically tested. Poor conditions on the breeding grounds at the end of the summer would push birds to depart prior to moult, while productive stopover locations would pull them. We tested for a relationship between moult-migration and breeding grounds aridity as measured by the normalized difference vegetation index. Our results strongly support the ‘push' aspect of the push–pull hypothesis and indicate that arid breeding grounds, primarily in western North America, would drive species to evolve stopover moult-migration, although this relationship may depend upon migration distance.