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Arctic warming and Golden eagle migrations: potential for desynchrony between spring and eagle arrival dates

Scott LaPoint, Lamont-Doherty Earth Observatory, Columbia Univ., sdlapoint@gmail.com
Eliezer Gurarie, University of Maryland, egurarie@umd.edu
Gil Bohrer, Ohio State University, bohrer.17@osu.edu
Sarah Davidson, Max Planck Institute for Ornithology, sdavidson@orn.mpg.de
Peter Mahoney, University of Washington, pmahoney29@gmail.com
Natalie Boelman, Lamont-Doherty Earth Observatory, Columbia Univ., nboelman@ldeo.columbia.edu (Presenter)

Understanding how animals adapt to climate change is a conservation priority, particularly in arctic landscapes where these changes are accelerated. Doing so however, remains challenging because animal behavior datasets are typically conducted at site- or population-specific scales and are often short term (e.g., 2-3 years). We have overcome this challenge by compiling a long-term (~25 years), large-scale (northwestern North America) dataset of > 0.5 million locations collected via 80 adult-aged golden eagles (Aquila chrysaetos) fitted with satellite and GPS data loggers. We used mechanistic range shift analyses to identify the locations and dates when each eagle performed a behavioral switch from a stationary phase (e.g., over-wintering or breeding) to migration and vice-versa. We annotated these spatio-temporal data with a suite of environmental data, including: % snow cover, snow depth, air temperature, and barometric pressure. We find age-based differences in Golden eagle spring migration phenologies. Adults begin and end migration earlier, with less intra- and inter-annual variability than subadults. The date adults arrive at their breeding grounds is consistent year after year, despite slight variations in departure date from their over-wintering grounds. We will use a survival analysis (e.g., Cox proportional-hazard regression model) to quantify the influence of the environmental variables on these dates. The age-based differences are interesting. Adults initiate migration when triggered by a fixed cue (i.e., photoperiod), preventing them from capitalizing on optimal migration conditions and also from arriving at their breeding grounds in spring earlier to synchronize with earlier spring arrival dates in the Arctic. Subadults are known to be more responsive to local environmental conditions, yet are unable to reproduce and contribute to their populations. Golden eagles exhibit some resiliency to changes in the arctic climate, but the impact of a potential desynchrony between adult arrival to and the conditions (e.g., local prey population pulses) at their Arctic breeding grounds warrants further investigation.

Associated Project(s): 

Poster Location ID: 22

Session Assigned: Wildlife and Ecosystem Services

 


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