A year in the life of an Idaho sage-grouse

Story and photos by Sara Morelli, Wildlife Biologist, Salmon Field Office

It was a bitter cold night in March 2015 when a certain sage-grouse female’s (SGF) life changed forever. That night she was designated “SGF4601” and thereafter, her movements would be closely monitored for the rest of her life. After being gently captured, she was fitted with a GPS “backpack” and released. Until her death four years later, her life was scrutinized by biologists, adding to our understanding of sage-grouse behaviors and their habitat.

In 2014, Idaho Fish and Game (IDFG), in partnership with the Bureau of Land Management (BLM) Salmon Field Office, began a project using GPS collars to track sage-grouse movements. Over the course of the study, biologists from both agencies learned surprising things about how sage-grouse move across the landscape.

Sage-grouse fly in the air with a snowy mountain in the background.
Using GPS tracking units, biologists found Idaho sage-grouse were traveling much farther than initially expected. A few Idaho sage-grouse made the journey over the Continental Divide to nest in Montana and then returned to Idaho for the winter.

“The collected GPS data has provided IDFG with the highest resolution data we’ve ever had for sage-grouse in Idaho, which allows us to look at fine-scale movements and habitat selection and ultimately relate those decisions the bird makes to their reproduction and survival,” explains Shane Roberts, Wildlife Research Manager for IDFG.

Although scientists have used radio telemetry to track sage-grouse for over twenty years in the Lemhi Valley, periodically birds would go missing—biologists couldn’t locate their radio signal—then a few months later they would find the bird again. GPS units eliminated that problem and now biologists discovered multiple birds were traveling over the Beaverhead Mountains and the Continental Divide, to nest in Montana and then return to Idaho for the winter. Other birds traveled over sixty miles south to wintering grounds and then returned north in the spring to nest. 

A sage-grouse sitting down in the brush
GPS transmitters allow biologists to pinpoint sage-grouse nest sites. After a tracked sage-grouse, such as this one, leaves their nest—either when their chicks hatch or the nest is depredated (pillaged)—field crews can monitor the vegetation at the site.

SGF4601 didn’t make these large movements; instead, she remained in the Lemhi Valley. Each year, she would winter west of Baker, Idaho (not far from Salmon, Idaho). Near the end of each March or in early April, she would begin her journey up the valley, stopping at each of five leks along the way. Once there, she would nest. SGF4601 attempted five nests over a three-year period all within half a mile of each other. A few nests were depredated (pillaged), one contained unfertilized eggs, and the eggs in one hatched. 

Map of SGF4601's movements and nest sites.
SGF4601 moved up and down the Lemhi Valley annually. Every spring, as she traveled from her wintering area in the north part of the valley, to her nesting habitat farther south, she would visit all five known leks along the route. Each of her five nests were within half a mile of each other.

In addition to the sage-grouse movement data, the Salmon Field Office collected vegetation at each nest site.

“Using the nest site data, we’re able to meet both the wildlife biologists’ and rangeland management specialists’ information needs in ongoing grazing permit renewals,” said Austen Foley, Salmon Field Office Rangeland Management Specialist.

A woman standing in a field and looking down at a BLM report.
Field crews measure vegetation characteristics at nest sites including sagebrush cover and height, perennial grass cover and height, and the number of preferred forb species. This data is used by wildlife biologists and rangeland management specialists to inform management decisions.

The Salmon Field Office is currently including data from SGF4601’s nest sites in an upcoming permit renewal. In the spring of 2018, for the first time, SGF4601 did not attempt a nest. In June, after her GPS signal remained in the same place for a few days, a quick search found her dead. However, SGF4601’s life provided lasting information as to how sage-grouse move seasonally and use habitat in the high elevation valleys of east-central Idaho. 

SGF4601’s leg band: a gray circular band with the numbers 4601 on it.
Biologists were able to retrieve SGF4601’s leg band after tracking her movements for four years. SGF4601 provided the Salmon Field Office and IDFG valuable information about sage-grouse movements and habitat in the Lemhi Valley.

The partnership between IDFG and BLM “has yielded a variety of results to inform management of both the sage-steppe habitat and sage-grouse resources,” said IDFG’s Roberts.

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