Tracking Post-Fledging Survival
A new research paper published in the journal Avian Conservation and Ecology by partners Bob Altman and Joel Geier and KBO scientist Sarah Rockwell presents the first estimates of post-fledging survival and site persistence of the Oregon Vesper Sparrow. The authors used mark-resight methodology, a method involving color-banding birds and observing them in the wild, to track the survival of fledglings in the weeks after they left their nests in the Willamette Valley of Oregon. The authors found that their survival estimates, derived from mark-resighting, were substantially higher than those found in previous studies using radio-tracking in other grassland songbirds. Post-fledging survival of Oregon Vesper Sparrows in the Willamette Valley was the highest ever reported for similarly sized grassland birds – 62.9% for the first nine weeks out of the nest, typically the most vulnerable time in a bird’s life. These differences may be due to either the naturally high survival of this subspecies in this region or a negative impact of radio-tracking on birds, particularly on fledglings, including entanglement and increased predation risk.
The paper concludes by acknowledging the greater effort needed for mark-resight methodology, but recommending it when possible as a less invasive and potentially more accurate alternative to radio-tracking for studying post-fledging survival in grassland birds, especially species of conservation concern. Post-fledging and juvenile survival are important pieces of information to estimate the population growth rate and extinction risk for this subspecies. The Oregon Vesper Sparrow is currently under review for listing as federally threatened or endangered, and the results presented in this paper will help the USFWS make this decision.
This study is a part of range-wide research on the imperiled Oregon Vesper Sparrow that KBO is conducting with the above-mentioned partners in the Willamette Valley, OR, and Ecostudies Institute in the Puget Lowlands, WA. Juvenile return rates at KBO’s field site on Howard Prairie are nowhere near as high as in the Willamette Valley – but this doesn’t necessarily mean that mortality is higher. It could mean that our young birds are more likely to disperse to other meadows than return to our study site. This is an important question in understanding the demography and possible causes of population decline in this subspecies and is an active area of research.
The study was funded primarily by the Oregon Department of Fish and Wildlife, with additional support from the American Bird Conservancy, U.S. Fish and Wildlife Service Multi-State State Wildlife Grant Program, U.S. Fish and Wildlife Service Migratory Birds Program, Oregon Wildlife Foundation, Wildlife Forever Fund, and Greenbelt Land Trust.
Citation:
Altman, B., J. Geier, and S. M. Rockwell. 2024. High post-fledging survival and site persistence using mark-resight methodology for Oregon Vesper Sparrows in the Willamette Valley, Oregon. Avian Conservation and Ecology 19(2):8. https://doi.org/10.5751/ACE-02706-190208
You can read the full article here: https://ace-eco.org/vol19/iss2/art8/
Join Frank Lospalluto for a haunting good time on the 25th at 5 pm. We will be traveling the Keno Access Rd. looking for Great Grey Owls and other silent predators of the night. The night will start at Rite Aid in Ashland to organize the carpool. Register below.
This presentation is to acquaint you with how to go to the refuge and what you might see when you get there. Maps of the refuge will be provided. A book will be featured that invites you to take some young person (or any age person) to the refuge to learn about the wonders of the waterfowl refuge. Klamath Refuge was designated the first waterfowl refuge in 1908.
Join Klamath Bird Observatory and the eBird NW Steering Committee to learn more about a new community science project, 
flycatching insects during its breeding season and stores acorns for its non-breeding seasons. Lewis’s Woodpeckers have been impacted by habitat loss and the decline of insect populations at breeding sites and along avian migration routes. The funds raised from this stamp will support KBO’s role in partnership-driven restoration work in oak woodlands, a critical habitat for this species, and research to uncover mysteries about its migration and identify opportunities for better-focusing conservation efforts throughout the Lewis’s Woodpeckers full annual cycle.