Conservation Projects: How are we learning about Streaked Horned Larks?
Ecostudies Avian Conservation Program is conducting several research and monitoring projects focused on different regional populations of streaked horned larks (Eremophila alpestris strigata). We use multiple techniques including point counts, nest monitoring, color banding, and GPS tagging, to evaluate lark populations to advance conservation and species recovery.
Streaked horned larks are a federally threatened grassland bird endemic to the lowlands west of the Cascade Range in Washington and Oregon. This formerly widespread subspecies is facing population declines as a result of habitat loss; expanding human development and agriculture, fragmentation due to forest succession, and invasive species like Scot’s broom, all contribute to degradation of the grassland, prairie, and dune habitats favored by these birds.
Ecostudies Avian Conservation Program works closely with our Restoration and Prescribed Fire Programs as well as many partners throughout the northwest to improve habitat and develop conservation strategies targeting streaked horned lark population recovery.
Streaked horned larks - Male above, female below. (Illustration by Marissa Gibson 2025)
Ecostudies biologists and Americorps members surveying for larks on a JBLM prairie site (Stephanie Augustine 2023)
We work with our partners at Joint Base Lewis-McChord (JBLM), a United States military installation south of Tacoma, WA, to monitor the breeding populations of streaked horned larks on base as part of their agreement with US Fish and Wildlife Service to achieve shared goals of supporting military readiness and mitigating impacts to sensitive species and their habitats. Collaborative monitoring and conservation efforts allow us to optimize habitat management for larks in areas with reduced military training conflicts. Our work includes understanding population size and distribution, evaluating factors influencing nest success and annual survival, and identifying migratory strategies and how they impact populations. Long-term, reintroduction of larks onto non-military lands will provide training relief to the military and support the recovery of the South Puget Sound regional population of larks.
Key Findings at JBLM: What have we learned so far?
- Prairie restoration to remove Scot’s broom and invasive grasses using prescribed fire and other tools has improved and increased streaked horned lark habitat quality and quantity.
- Nest success has improved from < 25% in the mid-2000s to an average of 40-60% over the past decade when the species was first federally listed and conservation measures to minimize human impacts to nests were implemented.
- GPS tags deployed in 2023 were recovered in 2024, and provided the first high-resolution spatial data for migratory and winter movements of larks.
Adult streaked horned lark in flight with a GPS tag antennae visible (Charlie Wright 2024)
Ecostudies biologist surveying for streaked horned larks in the dunes at sunrise (2024)
The coastal population of streaked horned larks has received limited monitoring over the past decade. In 2024, we implemented a new project to better understand the factors limiting this regional subpopulation with funding from the Biodiversity Grant program by Washington Department of Fish and Wildlife. We deployed GPS tags on adult and juvenile larks on the coast, complementing our existing work on JBLM, and will initiate nest monitoring in 2025. This project is conducted concurrently with monitoring of Western snowy plovers, with the goals of evaluating population vital rates, identifying impacts of recreation practices, and informing conservation strategies for both species.
Our goal is to develop a replicable survey protocol to provide robust information on distribution, abundance, and population trends. Beginning in 2022 with funding from the US Fish and Wildlife Service, we have conducted annual point count surveys, primarily on roadsides, informed by a predictive model of suitable lark habitat using satellite imagery.
Key Findings in the Willamette Valley: What have we learned so far?
- We are able to detect breeding streaked horned larks using roadside point counts, which is a novel approach for monitoring streaked horned larks – in the other regions, larks occur in more spatially limited, discrete populations which can be monitored using transect surveys through their occupied sites.
- Larks are more difficult to detect than initially expected, so we have had to adapt multiple facets of our trial survey protocol each year to maximize survey effectiveness.
Ecostudies biologists setting up a mist net at Wildhorse wind facility (Marissa Gibson 2023)
Long-term species recovery of the South Puget Sound regional population of streaked horned larks will require established breeding sites located off military training lands, and as larks have yet to independently re-colonize apparently suitable prairie sites in the region, this will likely only be achievable through translocation of individuals. From 2022-2023, Ecostudies conducted reintroduction trials at Wild Horse Wind and Solar Facility in Ellensburg, WA with the lark subspecies widely distributed across sagebrush-steppe habitat east of the Cascade Range, the dusky horned lark (Eremophila alpestris merilli). Trials served to evaluate the physical impacts to larks in a translocation process in a “soft-release” where birds are moved into an aviary at the new site for several days to acclimate with supplemental food, and then released.
Key Findings in the translocation trials: What have we learned so far?
- Larks at all phases of the breeding cycle – pre-breeding adults, adults with dependent, flightless nestlings, and independent flighted juvenile larks were captured and moved to an aviary outside of their breeding territory or capture location.
- No negative physical impacts were observed; all birds remained active and alert for the duration of their time in the aviary, and all nestlings fledged successfully.
- We believe these results suggest streaked horned lark translocations are safe and feasible at any life stage between pre- and post-breeding migration, and may be a critical tool to achieve population establishment at extirpated sites and advance overall species recovery.
Ecostudies biologists assembling an aviary at Wildhorse wind facility (2022)
A female streaked horned lark in hand (Stephanie Augustine 2024)
A streaked horned lark nestling being weighed before receiving color bands (Connor Tracey 2024)
Adult male streaked horned lark with GPS tag, Washington coast (Isabel Brofsky, 2024)
Critical Habitat: What threats are Streaked Horned Larks facing throughout their range?
Historically, streaked horned larks were found from the southern Willamette Valley in Oregon, north to the Georgia basin of British Columbia, Canada, including the Puget lowlands and coastal beaches of Washington. Today, the population is fragmented and substantially reduced, now found on wildlife refuges and agricultural lands in the Willamette Valley, sediment dredge islands in the Columbia River, a handful of coastal dunes in Pacific County, WA, and airfields and remnant prairie in the south Puget lowlands, primarily on Joint Base Lewis-McChord military installation.
Streaked horned lark populations are threatened by habitat loss through conversion, degradation, and fragmentation throughout their historic range. The flood plain habitat of the Willamette Valley has been reduced by development and agriculture, primarily grass seed production, hazelnut orchards, and livestock pasture. Lark habitat in the Columbia River region is sensitive to dredge material deposition timing and industrial development; in the coastal dunes, introduced grass species originally planted to prevent wind-driven movement of the dunes into developed areas crowd out native plants. Glacial prairies in the Puget Sound have been reduced by urbanization, Douglas fir encroachment, and the proliferation of invasive species like Scot’s broom and turfgrasses.
Habitat loss, coupled with introduced predators and extreme weather events, have contributed to population declines of streaked horned larks across their distribution, which led to their designation as a threatened species under the federal Endangered Species Act (USFWS 2012), endangered in the state of Washington (WDFW 2006), and sensitive in Oregon.
A male streaked horned lark photographed at JBLM (Charlie Wright 2024)
Looking Forward: What does future conservation of Streaked Horned Larks look like?
Ecostudies and partners continue to monitor lark populations in Washington and Oregon. Our work allows us to identify threats, restore habitat, and evaluate the impact of our conservation efforts on the population dynamics of this federally threatened bird. We will continue coordinating collaborative efforts toward habitat restoration, mitigating impacts to vulnerable life stages, and potentially implementing reintroduction of larks to conservation lands in our efforts to achieve stable, resilient populations and advance species recovery.
Wildflowers blooming at a restored prairie site on Joint Base Lewis-McChord (Connor Tracey 2024)
Public Involvement: How can I help?
While most of the on-the-ground research of streaked horned larks is conducted by biologists at Ecostudies and partner organizations, there are opportunities for the public to contribute toward streaked horned lark recovery.
- Citizen Science – Ecostudies uses eBird historical records and observation data allow us to make inferences between past and present management strategies. By submitting observations of streaked horned larks to eBird, the public can help biologists understand the bigger picture. To report lark sightings, Contact Us.
- Conservation at Home – Support for wild birds can be as simple as learning about your local wildlife, planting native species in your garden, and keeping your cats indoors.
- Policy – Public policy plays an important role in the conservation of endangered species, including streaked horned larks. You can be a voice for your feathered neighbors by supporting federal and state legislation that limits the use of dangerous pesticides, designates land for protection, and allocates funding for conservation work, like what we do here at Ecostudies.
- Join the Crew – Ecostudies offers employment opportunities for seasonal work in streaked horned lark conservation. Learn more about our currently available positions!
- Donate – Support Ecostudies Institute with donations!
A male streaked horned lark (Stephanie Augustine 2024)