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Tag: Western Purple Martin

An Evening with KBO


Join us at the KBO office on March 15th from 5:30 pm – 7 pm, to hear three talks by the KBO staff. This will be a hybrid event, and the in-person portion will be at the KBO office at 2425 Siskiyou Blvd, Ashland, OR. This is a free event with light refreshments provided.

GPS-tracking Western Purple Martins to Brazil and back

Dr. Sarah Rockwell will share photos and maps from KBO’s work to GPS-tag and track Western Purple Martins throughout their annual cycle. This research is uncovering migratory stopover and overwintering sites from Oregon to Brazil that will aid in international conservation efforts for this at-risk subspecies. Sarah’s work was recently shared in the Oregonian, you can read the article here.

KBO Banding Update

Dr. Ryan Terrill will discuss this year’s bird banding efforts at six sites throughout southern Oregon. Bird banders from four countries worked with KBO to research populations of local birds at six long-term field sites, all while collecting top-tier data, training other researchers, getting their banders certifications, and conducting public outreach.

Monitoring Bird Communities Through Point Count Surveys

Tom McLaren will give an overview of how Klamath Bird Observatory uses point-count surveys to monitor bird communities’ response to forest health treatments, habitat restoration, and management action. We will highlight how long-term monitoring has provided valuable information about songbird populations. Point count methods provide a cost-effective way to gather conservation-relevant information, which can be used in many ways.

Purple Martin Banding Efforts

by Sam Webb

Sarah Rockwell checking nest boxes with the box remover tool (c) Sam Webb

This spring marked the 4th year of our Purple Martin project. Klamath Bird Observatory has partnered with USFS and USGS to learn more about the western subspecies of Purple Martin. Our goal this year was to place GPS tags on 8 adult Purple Martins in order to track their migration routes and learn more about where they spend the winter.

Prior to banding, our crew boated out to check the nest boxes at the U.S. Army Corp of Engineers (USACE) Fern Ridge Reservoir to determine which were being used by Purple Martins. We checked each box for nesting activity so that we knew which ones were the most likely to have an adult Purple Martin roosting in it for the night.

Purple Martins naturally nest in cavities or old nest holes in snags or dying trees originally created by woodpeckers. Nesting locations become limited when snags are removed, or other bird species outcompete for nesting areas. The nest poles and boxes at Fern Ridge were made by USACE to provide Purple Martins with structures to roost and build their nests in. Designed to be removed with a unique tool, these nest boxes allow us to carefully bring them down, check for eggs or chicks, and catch adults.

While we were out checking nest boxes in the daytime, we took the opportunity to band any chicks that were old enough with a red band that had three easy-to-read numbers and an aluminum federal band. This will allow us to resight those individuals next year and learn more about the return rate of young Purple Martins or learn where else they might return to for their first breeding season.

Collaborator Joan Hagar of USGS banding a Purple Martin nestling (c) Sam Webb

After determining which nest boxes were likely to have adult Purple Martins roosting in them that night, we returned at dusk to try to catch and band the adults. We did this by floating quietly up to the poles and standing in the bow platform to quickly block as many cavity entrances as we could reach without the adults escaping. Once we caught an adult, we carefully took it out of the box and banded it using an aluminum federal band and the 3-numbered red band. We took additional measurements, looking at the health and size of the adult before choosing an appropriately sized GPS tag.

Sarah Rockwell and Sam Webb banding adult Purple Martin (c) Daniel Farrar

We fitted the GPS tag on the adult by slipping one loop of a harness made of stretchy jewelry cord around each of its legs and placing the tag on its back, similar to wearing a backpack. After the adult was banded and received its GPS tag, we double-checked the harness fit, carefully placed the martin back in its nest box, and set it back into position.

Adult male Purple Martin with its GPS tag (c) Sarah Rockwell

The following day, we paddled out once more to resight the adults that we banded the previous night. We spent time at each nest box to confirm that the adults still had their tags from the previous night and were comfortably delivering food to their young as usual.
These GPS tags that each Purple Martin received will take a location point every few days for up to the next year (depending on battery life) while the individual migrates to and from its wintering grounds. Due to its lightweight and compact size, the GPS tag is only able to collect location coordinates but not send them. Next year, we will return to find the adults with tags and catch them to retrieve the tags and data. Little is known about the migration route of the west coast population of Purple Martins or where they spend the winter. These data are critical for understanding their complete life cycle and for informing conservation efforts across their entire range. To read more about our first returnee and where she went, click here!


Our 2023 field efforts were supported by the Greenfield Hartline Habitat Conservation Fund and the Purple Martin Conservation Association.

Western Purple Martin

The unique western subspecies of Purple Martin is of conservation concern, roughly estimated at just 3,500 pairs. There is little known about the Western Purple Martins compared to the more abundant eastern subspecies (Rockwell 2019). Previous studies using light-level geolocators have revealed that Eastern Purple Martins largely overwinter in the heavily forested Brazilian Amazon. Still, Western Purple Martins appear to use a different overwintering area in southeastern Brazil, which may be more impacted by agriculture (Fraser et al. 2012). However, these data come from only a small number of individuals breeding in British Columbia that may not represent the entire subspecies. It is unknown whether other western populations, including martins that nest in Oregon, follow the same pattern.

Further, light-level geolocator data have a larger margin of error and are not precise enough to identify specific roosting sites that may need protection (McKinnon and Love 2018). Archival GPS tags provide unprecedented precision in determining these locations. We are using this technology to track migratory routes and overwintering sites used by Western Purple Martins and identify potential conservation opportunities in the non-breeding season. A better understanding of overwintering locations and migratory stopover sites used by Western Purple Martins, as potential threats originating on the non-breeding grounds have been identified in a recent ISSSSP Conservation Assessment as key information gaps needed to target conservation actions (Rockwell 2019).

From 2020-2022, a small team of researchers from KBO, USFS, and USGS captured adult Western Purple Martins breeding in coastal Oregon at night while they roost in their nestboxes. We have captured martins on the Siuslaw National Forest and McKenzie River Trust lands. We band the birds and outfit them with lightweight archival GPS tags that fit like a backpack with two leg loops to track their movements. There’s just one catch – to have a battery small and lightweight enough for a small songbird to carry, the tags cannot transmit data, only store it. Returning tagged birds must be recaptured following a year-long round-trip migration to retrieve the tag and its precious geospatial data. Due to these challenges, most tracking studies of this type have relatively small sample sizes; nevertheless, they have revolutionized our understanding of bird migration. Precise data on the winter whereabouts of a few Western Purple Martin individuals are enormously important compared to the absence of any precise data that we had before this study. Our objectives are to find locations of roost sites used during migration and winter and use this information to identify conservation partners and actions that can be taken during the non-breeding season.

Our first recaptured martin flew almost 7,000 miles to southeastern Brazil and then back again! KBO has joined the International Purple Martin Working Group, which focuses mostly on Eastern Purple Martins, to include our western subspecies in research and conservation activities with partners in more tropical locales. Stay tuned!

This work is supported by the U.S. Forest Service, Purple Martin Conservation Association, and U.S. Geological Survey. Photos provided by Lorelle Sherman.

Fraser, K. C., B. J. M. Stutchbury, C. Silverio, P. M. Kramer, J. Barrow, D. Newstead, N. Mickle, B. F. Cousens, J. C. Lee, D. M. Morrison, T. Shaheen, et al. 2012. Continent-wide tracking to determine migratory connectivity and tropical habitat associations of a declining aerial insectivore. Proceedings of the Royal Society B: Biological Sciences 279:4901–4906.

McKinnon, E. A. and O. P. Love. 2018. Ten years tracking the migrations of small landbirds: Lessons learned in the golden age of bio-logging. The Auk 135:834-856.

Rockwell, S. M. 2019. Conservation Assessment for Purple Martin (Progne subis). Interagency Special Status/Sensitive Species Program Conservation Assessments. USDA Forest Service Region 6 and USDI Bureau of Land Management, Oregon and Washington, 73 p.