Using new technology to track Kirtland’s Warblers
Tracking individual birds across the full annual cycle has long been the dream of ornithologists. While tracking technologies have improved tremendously and devices have become lighter and lighter each year, studying the same individual birds as they move thousands of miles through their annual cycle, has until now, largely proven impossible for all but the largest species.
In 2017, I began a project using Lotek’s new coded-radio tag technology and the Motus Network of automated telemetry towers (see picture below). In our pilot season, we tagged 63 Kirtland’s Warblers on Cat Island, The Bahamas. Using an array of 11 towers on the breeding grounds, were able to find, capture, and follow 60% of these individuals throughout the breeding season. With new funding from National Geographic, we continued this work in 2018, tagging 56 individuals on Cat Island and relocating 70% on the breeding grounds. This work has been funded for 2019 by USFWS and we hope to use these data for a variety of purposes.
First, we will directly study how winter habitat quality and body condition impacts departure timing, migration duration, arrival on the breeding grounds, and ultimately reproductive success. Many of these relationships have been established in American Redstarts and other species, but always using indirect methods such as stable isotopes. Second, we want to use this study system to better understand survival during migration. Previous correlational work has suggested that ~45% of Kirtland’s Warbler mortality happens during either fall or spring migration. Using the new coded tags, towers located throughout Florida, Georgia, Ohio, Ontario, and Michigan (see Motus Map here) we can begin to piece together where and when Kirtland’s Warblers are dying during migration. Third, in collaboration, with the University of Chicago and The Field Museum, we are investigating how gut microbiomes change within the same individuals, from wintering to breeding. Finally, we used our data from 2017 in combination with previous banding data to show that Kirtland’s Warblers have weak migratory connectivity. That research was published in Avian Conservation and Ecology.
download pdf here
Much more to come as we collect and analyze more data. For now check out this awesome article in Audubon Magazine