Kirtland’s Warbler Research

Tracking Kirtland’s Warbler Migration

Another technology we use to study bird movements is geolocation. Geolocator tags record ambient environmental information like light levels and, in newly developed tags, air pressure. We can analyze these stored data alongside global weather models to reconstruct a bird’s migratory route. Unlike satellite GPS and radio tags (such as Motus), geolocators do not receive or transmit location data, therefore using less battery power and making geolocators much lighter than other types of tags. This allows us to deploy geolocators on songbirds that are otherwise too small to safely track using other technologies. 

In collaboration with Nathan Cooper of the Smithsonian Migratory Bird Center (https://nathanwcooper.com/), Ward Lab student Katie Galletta is deploying over 200 multi-sensor geolocator tags on Kirtland’s warblers in Michigan to track their migration over the full annual cycle. The Kirtland’s warbler was on the brink of extinction when the original Endangered Species Act was established in 1973. After decades of effective conservation efforts, the species was delisted in 2019 but remains reliant on conservation. Our project aims to identify important stopover locations along Kirtland’s warbler migration routes, differences between male and female migratory behavior, potential anthropogenic hazards they face along the way, and differences between individual birds’ migrations across years. Using cutting-edge technology, our work seeks to both address a knowledge gap in the biology of this species that will inform more effective conservation, as well as to better our understanding of songbird migratory behavior and decision-making in general.

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A tagged female Kirtland’s warbler. The geolocator’s light sensor can be seen sitting on her lower back.

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A multi-sensor geolocator and adjustable harness ready to be deployed. At 0.5 grams, these tags are the same size and weight as a paperclip, and can record data for 13 months.