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Tag: Field work

Finding Oregon Vesper Sparrows: A Vital Census in the Cascade-Siskiyou National Monument

Why look for Oregon Vesper Sparrows?

It is estimated that only 3,000 individuals of this declining subspecies remain. The small population size of the Oregon Vesper Sparrow is well-documented, but the causes of its at-risk status are not. As with all migratory birds, population trends may be caused by factors on their breeding grounds, wintering grounds, or migration stopover areas.

Since 2018 Klamath Bird Observatory has been trying to understand the cause of this subspecies’ decline. Getting a snapshot of how many of these birds there are in the Cascade-Siskiyou National Monument – and where they are – is important baseline data. This information will be especially important if the Oregon Vesper Sparrow is listed as federally endangered or threatened – it is currently in review with the U.S. Fish and Wildlife Service for potential listing under the Endangered Species Act.

How many Oregon Vesper Sparrows live in the Cascade-Siskiyou National Monument?

This past summer, it was KBO’s goal to find out. Armed with paper maps, Avenza maps, GPS units, and binoculars, we bumped down endless back roads and completed the most rigorous inventory in the Monument to date. This included >7000 acres of potential montane meadow habitat, including some sizeable meadows that had never before been surveyed for Oregon Vesper Sparrows. We were interested in the bird’s abundance and distribution, and recording which meadows were occupied by this declining, at-risk subspecies. KBO surveyors spent many hours this summer hiking in steep terrain, getting our boots wet in the dewy grass, counting sparrows on transect surveys, and recording their locations on maps.

A picture of one of the field sites on the Cascade Siskiyou National Monument taken by field technician Lin Stern.

We surveyed 54 montane meadows in the Monument, mostly on public lands, and counted 140 Oregon Vesper Sparrows in 27 of them. Because this survey method is most likely to detect singing males (and most of those males will have mates), and there are also meadows on private property within the Monument that we could not survey, this number is almost certainly an underestimate. A striking finding was that there were more Oregon Vesper Sparrows than we thought, with many in quite small subpopulations scattered across meadows of varying sizes (some as small as 17 acres) all throughout the Monument. Only five meadows had 10 or more individuals detected; 75% of occupied sites had only 1-5 individuals. This is in addition to the three big meadows with the highest abundance of Oregon Vesper Sparrows just outside of the Monument – Owen’s Meadow, Lower Vesper Meadow, and Lily Glen – which have 30-50 pairs each. We now know that the Monument supports a substantial number of Oregon Vesper Sparrows, probably at least 10% of the global population which is estimated to be about 3,000 individuals.

We enjoyed the opportunity to visit all of these remote corners of our local Monument! It’s a wonderful resource to have in our collective “backyard” with a considerable diversity of habitats, including the montane meadows that support Oregon Vesper Sparrows and other grassland creatures. We are currently writing up a report to share our findings, and their conservation implications, with local BLM staff tasked with managing the Monument.

Editor’s Note: Funding for 2024 research activities was provided by the BLM National Conservation Lands Management Studies Support Program and Oregon Wildlife Foundation. KBO Field Technicians Lin Stern, Elijah Hayes, and Nate Trimble, and staff Sarah Rockwell and Sam Webb conducted surveys in the field.

Click here to learn more about the work Klamath Bird Observatory is doing around the Oregon Vesper Sparrow.

If you want to support this work, you can use this link to donate: https://klamathbird.org/product/donate/ 

 

Coming this Field Season: Oregon Vesper Sparrow and Technology

Spring has sprung, and migratory birds are making their way back to the Klamath Siskiyou Bioregion. Klamath Bird Observatory (KBO) is preparing by dusting off field gear, mapping out survey sites, and hiring summer staff. Each staff member has their own favorite thing to look forward to this field season: starting a new project, expanding an active project, or wrapping up data collection.

Dr. Sarah Rockwell, one of KBO’s Research Biologists, is excited to be expanding the Oregon Vesper Sparrow GPS tracking project. KBO will be deploying more tags at our Lily Glen study site near Howard Prairie. Sarah will also be training partner Bob Altman with the American Bird Conservancy to expand the study and place GPS tags on Oregon Vesper Sparrows in the Willamette Valley this summer. KBO will look at the Willamette birds’ migratory routes and overwintering areas, and compare them to the data KBO has gathered from birds in the Rogue Basin.

Oregon Vesper Sparrow (c) Frank Lospalluto

This summer KBO will also continue to deploy MOTUS tags on late-stage Oregon Vesper Sparrow nestlings. In previous years, very few juveniles have returned to the same meadow where they were hatched. To investigate this, Sarah will be putting MOTUS nodes out in new meadows surrounding past sites, expanding her search for these birds.

Oregon Vesper Sparrow Nest

Sarah is wrapping up collecting resight data for the Oregon Vesper Sparrow this summer – by resighting individually color-banded birds year after year, she can analyze their annual survival. KBO has also studied the sparrows’ nest success and habitat preferences in past years. The vegetation characteristics of sites where the sparrows choose to place their nests could be used to encourage land managers to plant beneficial vegetation. Other partners are collecting parallel data in the Willamette Valley, OR, and Puget Lowlands, WA, for similar use. The Oregon Vesper Sparrow is under review to potentially be added to the federally threatened and endangered species list, and Sarah hopes these data will help contribute to a decision.

This summer Science Director Jaime Stephens is excited about the ongoing Oregon Vesper Sparrow project. “KBO has been focusing our field research on this species for nearly a decade. A challenging part of science is that it can take a long time to gather the necessary data. In the next two years, KBO expects to have results available from this project that could be very impactful. These include nest success and breeding season habitat relationships, and as that wraps up we are moving on to MOTUS and GPS tagging to study non-breeding season movements. We are finishing an exciting part and moving on to an even more exciting part of the project.”

To learn more about the Oregon Vesper Sparrow and KBO’s conservation science projects click here. “Coming this Field Season” is a blog series highlighting the different projects that KBO staff are working on this summer. Subscribe to the blog and follow us on Facebook and Instagram to be notified of the next article.