Klamath Bird Observatory
$29,998  Coast Range   Willamette Valley 

The unique western subspecies of Purple Martin, an Oregon Conservation Strategy Species, is estimated at just 3,500 pairs in the Pacific Northwest. Determining factors that limit population size in a migratory bird requires understanding what threats they may face in different parts of the year – and thus, the first step is understanding where those locations are. A geolocator study revealed that Western Purple Martins may use a separate wintering area than the eastern subspecies, but the sample size was small, and location data obtained from geolocators are not very precise. A better understanding of winter locations and migratory stopover sites used by Western Purple Martins, and potential threats originating during the non-breeding season, are key information gaps needed to target conservation actions. In 2020-2022, we captured 23 martins breeding in coastal Oregon and fit them with lightweight archival GPS tags to track their movements – the very first study to do so with this subspecies. Three have been recaptured so far, revealing a tantalizing first look at the migratory routes, extended fall stopovers, and wintering locations in southeastern Brazil used by this imperiled bird, but more data are needed. Eight GPS tags were deployed at Fern Ridge Reservoir in 2023, a site where we expect return rates to be higher. To increase our sample size, this project aims to collect additional data, deploying 10 GPS tags on adult Western Purple Martins in 2025. We will resight and recapture returning GPS-tagged birds in 2026. Our objectives are to 1) obtain precise locations of roost sites used during migration and winter, 2) obtain daytime foraging locations during the non-breeding season, and 3) use GIS to analyze habitat types, land ownership, and land cover change at these sites, including sites in Oregon. The novel data collected during this project will contribute to our long-term goal of stabilizing and increasing the population of Western Purple Martin.