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Lewis's woodpecker, Gray catbird
Research Projects: 
MOTUS Avian, Avian Ecology
As birds returned to the Bitterroot Valley, we anxiously awaited detections of any birds that we had fitted with nanotags last year. From March to June, we checked stations (Figure 1) every couple of weeks for new detections. So far, we’ve detected four Lewis’s Woodpeckers, four Gray Catbirds, three Common Nighthawks, and one Swainson’s Thrush.

Figure 1. Blue circles show locations of stations in the Intermountain West Collaborative Motus Project as of spring 2020.

Lewis’s Woodpeckers

We first detected signals from a Lewis's Woodpecker nanotag on April 29. Three more detections of this species soon followed. Of these four, two of them settled in the same area as they had last year, but we do not know if they're using the same nest. The other two woodpeckers passed through the valley, and we have not detected them since (Figure 2). We searched for them in the territories they used last year, but found other birds occupying the territories. This is consistent with the behavior we’ve observed of color banded Lewis’s Woodpeckers: fewer than 10% of them have nest-site fidelity between years. We hope we can use the Motus network to understand where they go once they move on.

Figure 2. Arrows and dates (in yellow or pink) show the movements of two previously resident Lewis’s Woodpeckers during spring 2020.

Gray Catbirds
This spring, we detected three Gray Catbirds. These birds were tagged on September 9, 2019 by The Breuner Lab and the Bird Ecology Lab at the University of Montana. One catbird arrived on June 1 and traveled across the Bitterroot Valley on the same day (Figure 3). We are excited to see if the bird stays in the area during the breeding season.

Figure 3. Yellow text depicts the arrival dates and times of a Gray Catbird returning this spring.

Station profiles
The Motus station on Lee Metcalf National Wildlife Refuge in Stevensville detected the majority of birds that flew back to MPG Ranch during spring migration. The station on the Teller Refuge in Corvallis intercepted a subset of these birds. Teller and Lee Metcalf stations have become the heart of our Motus station array in the Bitterroot Valley.

Transmitter issues
We've seen two Lewis's Woodpeckers and one Brown-headed Cowbird with transmitters attached, but we’ve detected no signal from them. We're disappointed with this technology failure. The woodpeckers’ transmitters had an advertised lifespan of at least 950 days and the cowbird’s transmitter was supposed to last at least 350 days. It’s difficult to say how many additional non-functioning transmitters exist. A low number of year to year detections may also correspond to birds dispersing towards different breeding sites. We’re working with Lotek to understand and resolve this issue.

This Lewis's Woodpecker shows its unique combination of color bands. Its Motus tag antenna protrudes beyond its wingtips, but we’ve detected no signals from it using a handheld receiver.

Upcoming work
Biologists from MPG Ranch have already tagged 16 Lewis’s Woodpeckers this season and will start work with Common Nighthawks this week. UMBEL’s crew has tagged two presumably migrant Swainson’s Thrushes.

For more information on tag deployment and species studied, see these updates:
January 14, 2020, Tracking Wildlife Migration with Motus
August 13, 2019, Summer 2019 Motus Update.

Thanks to these landowners and managers for hosting Motus stations:
Lee Metcalf National Wildlife Refuge: Tom Reed
Teller Wildlife Refuge: Sam Lawry
KBK Ranch: Kit Tilly and Joe Rimensberger

About the Author

Kate Stone

Kate graduated from Middlebury College with a B.A. in Environmental Studies and Conservation Biology in 2000. She pursued a M.S. in Forestry at the University of Montana where her thesis focused on the habitat associations of snowshoe hares on U.S. National Forest land in Western Montana. After completing her M.S. degree in 2003, Kate alternated between various field biology jobs in the summer and writing for the U.S. Forest Service in the winter. Her fieldwork included projects on small mammal response to weed invasions, the response of bird communities to bark beetle outbreaks and targeted surveys for species of concern like the black-backed woodpecker and the Northern goshawk. Writing topics ranged from the ecology and management of western larch to the impacts of fuels reduction on riparian areas.

Kate coordinates bird-related research at the MPG Ranch. She is involved in both original research and facilitating the use of the Ranch as a study site for outside researchers. Additionally, Kate is the field trip coordinator and website manager for the Bitterroot Audubon Society. She also enjoys gardening and biking in her spare time.