Atmospheric pressure predicts probability of departure for migratory songbirds

Nathan W Cooper; Bryant C Dossman; Lucas E Berrigan; J Morgan Brown; Dominic A Cormier; Camille Bégin-Marchand; Amanda D Rodewald; Philip D Taylor; Junior A Tremblay; Peter P Marra

doi:10.1186/s40462-022-00356-z

Atmospheric pressure predicts probability of departure for migratory songbirds

Mov Ecol. 2023 May 1;11(1):23. doi: 10.1186/s40462-022-00356-z.

Authors

Nathan W Cooper¹, Bryant C Dossman^{2

3}, Lucas E Berrigan^{4

5}, J Morgan Brown^{4

6}, Dominic A Cormier⁴, Camille Bégin-Marchand⁷, Amanda D Rodewald³, Philip D Taylor⁴, Junior A Tremblay⁷, Peter P Marra²

Affiliations

¹ Migratory Bird Center, Smithsonian's National Zoo and Conservation Biology Institute, MRC 5503, 3001 Connecticut Ave. NW, Washington, DC, 20013, USA. coopern@si.edu.
² Department of Biology and McCourt School of Public Policy, Georgetown University, 37th and O Streets NW, Washington, DC, 20057, USA.
³ Cornell Lab of Ornithology and Department of Natural Resources and the Environment, Cornell University, 159 Sapsucker Woods Rd, Ithaca, NY, 14850, USA.
⁴ Department of Biology, Acadia University, 33 Westwood Avenue, Wolfville, NS, B4P 2R6, Canada.
⁵ Motus Wildlife Tracking System, Birds Canada, Port Rowan, ON, N0E 1M0, Canada.
⁶ Wildlife Conservation Society Canada, 169 Titanium Way, Whitehorse, YT, Y1A 0E9, Canada.
⁷ Wildlife Research Division, Environment and Climate Change Canada, 1550 Av. D'Estimauville, Québec, QC, G1J 0C3, Canada.

Abstract

Background: Weather can have both delayed and immediate impacts on animal populations, and species have evolved behavioral adaptions to respond to weather conditions. Weather has long been hypothesized to affect the timing and intensity of avian migration, and radar studies have demonstrated strong correlations between weather and broad-scale migration patterns. How weather affects individual decisions about the initiation of migratory flights, particularly at the beginning of migration, remains uncertain.

Methods: Here, we combine automated radio telemetry data from four species of songbirds collected at five breeding and wintering sites in North America with hourly weather data from a global weather model. We use these data to determine how wind profit, atmospheric pressure, precipitation, and cloud cover affect probability of departure from breeding and wintering sites.

Results: We found that the probability of departure was related to changes in atmospheric pressure, almost completely regardless of species, season, or location. Individuals were more likely to depart on nights when atmospheric pressure had been rising over the past 24 h, which is predictive of fair weather over the next several days. By contrast, wind profit, precipitation, and cloud cover were each only informative predictors of departure probability in a single species.

Conclusions: Our results suggest that individual birds actively use weather information to inform decision-making regarding the initiation of departure from the breeding and wintering grounds. We propose that birds likely choose which date to depart on migration in a hierarchical fashion with weather not influencing decision-making until after the departure window has already been narrowed down by other ultimate and proximate factors.

Keywords: Atmospheric pressure; Cloud cover; Departure probability; Migration; Precipitation; Weather; Wind profit; Wintering.