Range-wide Oregon Vesper Sparrow Project

Vesper Sparrows (Pooecetes gramineus) are found throughout the northern half of North America and Canada. In the Pacific Northwest breeding populations of Oregon Vesper Sparrow (Pooecetes gramineus affinis), one of four subspecies, historically spanned from southwest British Columbia, western Washington and Oregon, to northwestern California. Breeding Oregon Vesper Sparrows have been extirpated from British Columbia and northwestern California.  Due to these dramatic declines, the subspecies has been petitioned for listing as endangered or threatened under the U.S. Endangered Species Act.  The population is estimated to be fewer than 3,000 individuals.  Vesper Sparrows (Pooecetes gramineus) are found throughout the northern half of North America and Canada. In the Pacific Northwest breeding populations of Oregon Vesper Sparrow (Pooecetes gramineus affinis), one of four subspecies, historically spanned from southwest British Columbia, western Washington and Oregon, to northwestern California. Breeding Oregon Vesper Sparrows have been extirpated from British Columbia and northwestern California.  Due to these dramatic declines, the subspecies has been petitioned for listing as endangered or threatened under the U.S. Endangered Species Act.  The population is estimated to be fewer than 3,000 individuals.  


Collaborators are conducting field research to determine why this species has been in decline, and what can be done to turn these negative trends around.  Klamath Bird Observatory, American Bird Conservancy, Center for Natural Lands Management, and a master’s student from Southern Oregon University (SOU) are tackling this unique opportunity to study Vesper Sparrows together, throughout their breeding range, in order to develop strategies for stabilizing and recovering populations.

Ongoing Studies

The small population size of Oregon Vesper Sparrow is well documented, but the reasons remain speculative. Declines may be caused by habitat factors on their breeding or wintering grounds: loss and degradation of habitat due to development, fire suppression, exotic species, and agriculture. Oregon Vesper Sparrows may also be declining due to factors that affect small population size.  Small populations lack genetic diversity and are less able to rebound after environmentally harsh years, breeding seasons with low productivity, disease, and natural disasters such as fires, floods, and drought. To begin to disentangle these potential causes of population decline, a group of collaborators are contributing to a range-wide study to assess limiting factors and inform conservation action. The three year study will assess productivity, survivorship, dispersal/recruitment, and habitat in order to identify where within the annual life cycle conservation actions are needed. Klamath Bird Observatory’s work with the Rogue Basin population is being replicated by partners in the Umpqua and Willamette Valleys in Oregon and Puget Lowlands in Washington. 

Continue Reading

Print Email

Engagement and Education

The Vesper Sparrow is considered a “little brown job.” You know, those streaky brown sparrows and dull-colored females that we all struggle with? If no one knows about this “little brown job,” how can it ever be protected?  The story of the Oregon Vesper Sparrow needs to be shared with birders and non-birders alike. Local Rogue Valley citizens were involved in an end-of-season Vesper Sparrow count to help share the story about this declining species, and assist researchers in gathering fall population estimates. Fourteen volunteers attended an education presentation on the Vesper Sparrow, and then spent a total of 76 hours in the field and found 124 Vesper Sparrows at Howard Prairie in August! Klamath Bird Observatory staff could not have gotten these numbers without their help.  In 2019 more volunteers will be needed to assist with the project, so if you are interested in helping out, stay tuned for opportunities.

Print Email

Notes From the Field

Vesper Sparrow banding (c) Daniel Thiede

In 2018 Klamath Bird Observatory staff, interns, and SOU master’s student began monitoring the Rogue Basin birds located at Howard Prairie, near Ashland, Oregon.  With so much research happening in one place, we know these birds like we know our best friends! 


Jim Lawrence, KBO Field Technician, spent his spring mornings watching Vesper Sparrows from his lawn chair.  The birds arrived from their wintering grounds in April and began to settle in for the summer.  Jim witnessed them defending their territories and attracting mates, then pair up and initiate nest building.  He saw them incubate their eggs and raise their young.  Jim watched breeding pairs build 25 nests and rear 62 fledglings, the next generation of Vesper Sparrows. His efforts will help track reproductive success and fledgling survival. 

Continue Reading

Print Email