Eremophila alpestris strigata
Streaked Horned Lark
Species group: Birds
Found in: Species of concern in the Puget Sound watershed
Streaked Horned Lark (Eremophila alpestris strigata)
This article was originally published by the Washington Department of Fish and Wildlife as part of its annual report Threatened and Endangered Wildlife in Washington.
Eremophila
Humid coastal belt of sw Br. Col. and nw US w of the Cascades.
Clements, J. F., T. S. Schulenberg, M. J. Iliff, B.L. Sullivan, C. L. Wood, and D. Roberson. 2012. The eBird/Clements checklist of birds of the world: Version 6.7. Downloaded from http://www.birds.cornell.edu/clementschecklist/downloadable-clements-che...
Cornell Laboratory of Ornithology
Currently: Absent
Global Range: (20,000-200,000 square km (about 8000-80,000 square miles)) This subspecies historically bred in prairie and open coastal habitats from the southwestern corner of British Columbia (southeastern Vancouver Island, lower Fraser River Valley) through the Puget trough and Willamette Valley (as far south as Eugene, Oregon) and into the Rogue River Valley (from Medford north to Eagle Point) (COSEWIC 2003, Pearson and Altman 2005, Environment Canada 2007); it was also found on open coastal habitats in western Washington (see Pearson and Altman 2005). U.S. and Candian surveys indicate that this subspecies currently breeds on prairie remnants (n = 2) and airports (n = 4) in the southern Puget lowlands, on beaches and accreted lands near Grays Harbor and Willapa Bay (n = 4), on dredge spoil islands in the Columbia River (n = 6), an industrial site along the lower Columbia River in Oregon, and on a number of agricultural, pasture, grass, and mudflat habitats in the Willamette Valley from Portland to Eugene (Pearson and Altman 2005); in addition, it has been reported as an irregular breeder on the south jetty of the Columbia River (M. Patterson, pers. comm., cited by Pearson and Altman 2005).
Recent surveys found most birds wintering in the Willamette Valley (Robinson and Moore 2005), with fewer birds on Columbia River islands and its floodplain, the Washington coast, and on a Puget Sound airport and prairie (see Pearson and Altman 2005). In addition, some may winter on the southern Oregon coast (Coos County; subspecies unknown but may be strigata) (and irregularly on the northern Oregon coast) (see Pearson and Altman 2005).
A rough estimate of range extent is 85,000 square kilometers.
Comments: Habitat consists of large expanses of bare or thinly vegetated land, including fields, prairies, dunes, upper beaches, airports, and similar areas with low/sparse grassy vegetation; see Pearson and Altman (2005) for further details.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Available evidence suggests that birds in the Puget lowlands are migrating south for the winter (Pearson and Altman 2005); multiple observations of banded birds throughout the winter in the Willamette Valley, Columbia River and on the Washington Coast suggest that some of these birds are staying in these regions throughout the winter (Pearson and Altman 2005).
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 6 - 20
Comments: In a range-wide review, Pearson and Altman (2005) listed 20 breeding areas, including 6 in the Puget Trough, 4 on the Washington coast, 7 along the lower Columbia River, and 3 in the Willamette Valley (not counting incidental sightings).
Global Abundance
250 - 1000 individuals
Comments: Results from winter and breeding surveys suggest that the entire breeding population of this subspecies is approximately several hundred birds and likely less than 1,000 (Pearson and Altman 2005, Stinson 2005).
Current Listing Status Summary
Status: Proposed Threatened
Lead Region: Pacific Region (Region 1)
Where Listed:
For most current information and documents related to the conservation status and management of Eremophila alpestris strigata, see its USFWS Species Profile
US Fish and Wildlife Service - Endangered Species Program
Rounded National Status Rank: NX - Presumed Extirpated
Rounded National Status Rank: N2 - Imperiled
Rounded Global Status Rank: T2 - Imperiled
Reasons: Small range currently restricted to Washington and Oregon; significant past and probably ongoing declines; although there are about 20 occurrences, all but a handful are probably not viable in the long term; 500-1000 individuals remain; primary cause of decline is ongoing habitat loss, fragmentation, and degradation.
Intrinsic Vulnerability: Not intrinsically vulnerable
Environmental Specificity: Very narrow. Specialist or community with key requirements scarce.
Global Short Term Trend: Decline of 10-50%
Comments: Recent estimates of population growth rate of populations in the Puget lowlands, lower Columbia River, and the Washington coast (but not including populations in the Willamette Valley of Oregon) indicate that the streaked horned lark population is declining rapidly (40% per year) (Pearson et al. 2008). Estimates of immigration were not built into this estimate, so the decline in absolute population size could be less than 40% per year if the population is being rescued by immigration. This rapid population decline is apparently the result of both low fecundity and low survival.
Breeding Bird Survey (BBS) results for 1980-2007 for Oregon and Washington indicate a statewide decline in horned larks (reduction of 4.6 and 1.2 percent per year, respectively). Horned Larks were recorded in only a few BBS routes in British Columbia, where the decline has been drastic (reduction of around 15 percent per year). Note that these BBS data include mostly populations other than subspecies strigata but indicate the likelihood of an ongoing decline throughout the region occupied by the streaked horned lark.
Global Long Term Trend: Decline of >90%
Comments: The breeding range has contracted over time; this subspecies no longer breeds in the northern Puget trough (San Juan Islands and other Puget Sound sites north of Tacoma), southern British Columbia (COSEWIC 2003, Environment Canada 2007), along the Washington Coast north of Grays Harbor, or in the Rogue River Valley (see Pearson and Altman 2005).
No historical estimates of population size are available, but this subspecies has apparently suffered a "severe decline" (Beauchesne and Cooper 2002). It is now rare and has been extirpated from much of its range (USFWS 2003). It was originally described as very abundant in the prairies of Puget Sound region (Suckely and Cooper 1860, Dawson and Bowles 1909) and was recorded as breeding "commonly at times" in the San Juan Islands after 1946, but last breeding record there was 1962 (Rogers 2000). In the 1940s, it was was a "very common permanent resident" in the southern Willamette Valley (Gullion 1951). In western Oregon, it was noted as a common breeder in the 1930s, even "particularly abundant" in Polk and Yamhill Counties (Gabrielson and Jewett 1940). However, there may have been confusion between subspecies, and E. a. strigata may never have been that common there (Rogers 2000). The small population in British Columbia declined to extirpation over the last four decades. The last confirmed breeding record was in 1978; and the last summer sighting at Sea Island was in 1987, although a few may have persisted in the central Fraser Valley until the mid-1990s (Campbell et al. 1997, Beauchesne and Cooper 2002).
Prairie habitat has declined to less than 1% of its former extent in the Willamette Valley and to less than 3% in the Puget Sound area (Altman 2000, Crawford and Hall 1997). Overall, it has been estimated that less than one percent of the native savanna and grassland remains in the range of the streaked horned lark (Oregon-Washington Partners in Flight 2000).
Degree of Threat: High
Comments: Significant threats include destruction and degradation of habitat as a result of agricultural practices, urbanization, forest invasion, invasion of non-native vegetation, fire suppression, and changes in ecological processes that create suitable horned lark habitat; disturbance by humans; nest destruction caused by mowing of habitat during the nesting season; nest predation; and small population size (see Pearson and Altman 2005 for further details).
The primary threat is the loss, fragmentation, and degradation of suitable breeding habitat. Habitat has been and continues to be lost through urbanization, agricultural intensification, fire suppression, and alien species invasion (Altman 2000, Beauchesne and Cooper 2002). At least 60% of the remaining Oregon population is not secure (E. Scheuering, pers. comm.). In Washington, however, the habitat of the key remaining occurrences is more or less secure. Because the populations breeding at most occurrences are so small, they are threatened with extirpation by a host of unpredictable environmental events and fluctuations.
In the Willamette Valley, it is estimated that less than 1 percent of the native grassland and savanna remains (Altman 2000). There, the prime causes of habitat loss and degradation are conversion of grassland to agriculture; homes and other human development; encroachment of woody vegetation because of fire suppression; and encroachment onto prairies by alien plant species such as broom (Cytisus scoparius) and grasses (e.g. Holcus sp. and Arrhenatherum elatius). In the south Puget Sound region, only 3 percent of the historic prairie is considered to be intact (Crawford and Hall 1997).
On the Columbia (and probably the Fraser River) floodplain, the building of dams and dikes has eliminated seasonally flooded prairies and allowed riparian forests to grow (Rogers 2000).
At sites in Washington State that are not noticeably threatened by habitat loss, the primary threat comes from recreational and military use of the sites (J. Fleckenstein, pers. comm.). On San Juan Island, the species has disappeared from habitat that has not noticeably changed; there, however, introduced predators such as red foxes and ferrets may have reduced the numbers of ground-nesting birds (Rogers 2000).
In Canada, limiting factors include current scarcity of suitable habitat, historical decline of suitable habitat, increased human disturbance in remaining habitats, increased predation pressure related to increased urbanization, invasion of exotic plants, increased pesticide use, and severe decline of a source population for immigration (COSEWIC 2003).
Management Requirements: Several conservation measures have been developed to help the streaked horned lark recover from its current low population level. Land managers are encouraged to: (1) use mechanical or natural means to maintain or create bare ground and sparsely vegetated areas within or adjacent to areas of suitable habitat; (2) create suitable habitat in areas secure from disturbance by vehicles, predators (e.g., away from edges of fields), and flooding events (e.g., upland hummocks, dikes, etc.) to reduce the species' vulnerability and potentially increase nest success and population size; and (3) use moist soil management to create seasonal mudflats where possible (Oregon-Washington Partners in Flight 2000).
Management recommendations include: minimizing human activities in breeding areas from early March until early August; restoring habitats consisting of sparsely vegetated areas composed of short annual grasses, and with a high percentage of bare ground; creating and maintaining "high quality prairie habitat" with more open spaces between plants; continuing reduction of Scotch broom invasion; eliminating potential sources of food for predators, including covering garbage and food scraps; prohibiting all recreational activities near nesting areas; and modifying mowing regimes to avoid nest destruction (Washington Department of Fish and Wildlife).
Biological Research Needs: See Pearson and Altman (2005) (http://www.wdfw.wa.gov/wlm/research/papers/streaked_horned_lark/).
Global Protection: Few (1-3) occurrences appropriately protected and managed
Comments: Very few breeding or wintering sites are protected, and no sites are managed primarily for horned larks (Pearson and Altman 2005).
Populations occur in Willapa National Wildlife Refuge and Damon Point Wildlife Management Area in Washington and Baskett Slough National Wildlife Refuge in Oregon; these areas are managed for wildlife, but it is not known whether the management regimes are compatible with Streaked Horned Lark needs.
Of the six known streaked horned lark populations in the southern Puget Sound lowlands, four occur on Fort Lewis Military Installation and McChord Air Force Base. The military bases maintain some of these populations because the vegetation is kept low by mowing, there are frequent fires that eliminate Scotch broom, and training activities maintain the sparse vegetation favored by horned larks.
COSEWIC (2003) reported the following information regarding land ownership and management in Canada. A few former breeding sites in Canada are located within regional parks on Sea Island and Iona Island. Iona Beach Regional Park includes a few hectares of sand dune and spit habitat, but some of that habitat is impacted by an active log salvage operation. The Sea Island Conservation Area, adjacent to Vancouver International Airport and within the area formerly used by nesting streaked horned larks, contains 140 ha of woodlands, wetlands, and old field habitat and is administered by Environment Canada. This area could contain suitable habitat but only if fields are mowed short. An unknown amount of old-field habitat occurs in Richmond's Terra Nova Natural Area reserve, but its suitability as habitat for the horned larks is uncertain. A small amount of potential habitat still remains on privately owned agricultural land. Other potential breeding habitat occurs at Vancouver International Airport, Boundary Bay Airport, Victoria International Airport, Nanaimo Airport, Abbotsford Airport, and Chilliwack Airport. None of these sites are managed to conserve habitat for horned larks.
Stewardship Overview: See Pearson and Altman (2005) (http://www.wdfw.wa.gov/wlm/research/papers/streaked_horned_lark/) for management and research recommednations.
alouette hausse-col strigata
Animals, Vertebrates - Birds - Perching Birds
Animalia - Craniata - Aves - Passeriformes - Alaudidae - Eremophila - Horned lark subspecies and patterns of geographic variation are in need of review (see Beason 1995). Genetic data for horned larks from the Puget Trough, coastal Washington, the lower Columbia River, Alaska, alpine Washington (Cascades but not the Olympic Mountains), eastern Washington, eastern Oregon, and California indicate that the streaked horned lark is unique, isolated, and has little genetic diversity (Drovetski et al. 2005).
true - true - false - Available evidence suggests that birds in the Puget lowlands are migrating south for the winter (Pearson and Altman 2005); multiple observations of banded birds throughout the winter in the Willamette Valley, Columbia River and on the Washington Coast suggest that some of these birds are staying in these regions throughout the winter (Pearson and Altman 2005).
G5T2
<img src="http://www.natureserve.org/explorer/servlet/GetMapGif?CA.BC=SX&US.OR=S2&US.WA=S1" alt="Conservation Status Map" style="width: 475px; height: auto;" />
F - 20,000-200,000 square km (about 8000-80,000 square miles) - F - This subspecies historically bred in prairie and open coastal habitats from the southwestern corner of British Columbia (southeastern Vancouver Island, lower Fraser River Valley) through the Puget trough and Willamette Valley (as far south as Eugene, Oregon) and into the Rogue River Valley (from Medford north to Eagle Point) (COSEWIC 2003, Pearson and Altman 2005, Environment Canada 2007); it was also found on open coastal habitats in western Washington (see Pearson and Altman 2005). U.S. and Candian surveys indicate that this subspecies currently breeds on prairie remnants (n = 2) and airports (n = 4) in the southern Puget lowlands, on beaches and accreted lands near Grays Harbor and Willapa Bay (n = 4), on dredge spoil islands in the Columbia River (n = 6), an industrial site along the lower Columbia River in Oregon, and on a number of agricultural, pasture, grass, and mudflat habitats in the Willamette Valley from Portland to Eugene (Pearson and Altman 2005); in addition, it has been reported as an irregular breeder on the south jetty of the Columbia River (M. Patterson, pers. comm., cited by Pearson and Altman 2005).
Global Range Code:
20,000-200,000 square km (about 8000-80,000 square miles)