Daily Rules, Proposed Rules, and Notices of the Federal Government
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The coordinates or plot points or both from which the critical habitat maps are generated are included in the administrative record for this rulemaking and are available at
For those species for which we are proposing listing, we have determined that these species are impacted by one or more of the following factors to the extent that the species meets the definition of an endangered or threatened species under the Act:
• Habitat loss through conversion and degradation of habitat, particularly from agricultural and urban development, successional changes to grassland habitat, military training, and the spread of invasive plants;
• Inadequate existing regulatory mechanisms that allow significant threats such as habitat loss;
• Other natural or manmade factors, including low genetic diversity, small or isolated populations, low reproductive success, and declining population sizes;
• Aircraft strikes and training at airports; and
• Pesticide use or control as a pest species.
• Approximately 6,875 acres (ac) (2,782 hectares (ha)) are proposed for designation as critical habitat for the Taylor's checkerspot butterfly.
• Approximately 12,159 ac (4,920 ha) are proposed for designation as critical habitat for the streaked horned lark.
We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from the public, other concerned governmental agencies, Native American tribes, the scientific community, industry, or any other interested parties concerning this proposed rule. We particularly seek comments concerning:
(1) The species' biology, range, and population trends, including:
(a) Habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range including distribution patterns;
(d) Historical and current population levels, and current and projected trends; and
(e) Past and ongoing conservation measures for the species, its habitat or both.
(2) The factors that are the basis for making a listing determination for a species under section 4(a) of the Act (16 U.S.C. 1531
(a) The present or threatened destruction, modification, or curtailment of its habitat or range;
(b) Overutilization for commercial, recreational, scientific, or educational purposes;
(c) Disease or predation;
(d) The inadequacy of existing regulatory mechanisms; or
(e) Other natural or manmade factors affecting its continued existence.
(3) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to this species and existing regulations that may be addressing those threats;
(4) Additional information concerning the historical and current status, range, distribution, and population size of this species, including the locations of any additional populations of this species;
(5) Any information on the biological or ecological requirements of the species, and ongoing conservation measures for the species and its habitat;
(6) The reasons why we should or should not designate areas as “critical habitat” under section 4 of the Act (16 U.S.C. 1531
(7) Specific information on:
(a) The amount and distribution of habitat for the Taylor's checkerspot butterfly and streaked horned lark;
(b) What areas that were occupied at the time of listing (or are currently occupied) and that contain features essential to the conservation of the species should be included in the designation and why;
(c) Special management considerations or protection that may be needed in critical habitat areas we are proposing; and
(d) What areas not occupied at the time of listing are essential for the conservation of the species and why.
(8) Land use designations and current or planned activities in the subject areas and their possible impacts on proposed critical habitat.
(9) Information on the projected and reasonably likely impacts of climate change on the Taylor's checkerspot butterfly and streaked horned lark, and on proposed critical habitat.
(10) Any probable economic, national security, or other relevant impacts of designating any area that may be included in the final designation; in particular, any impacts on small entities or families, and the benefits of including or excluding areas that exhibit these impacts.
(11) Whether any specific areas we are proposing for critical habitat designation should be considered for exclusion under section 4(b)(2) of the Act, and whether the benefits of potentially excluding any specific area outweigh the benefits of including that area under section 4(b)(2) of the Act.
(12) Additional information pertaining to the promulgation of a special rule to exempt take of the streaked horned lark on civilian airports, agricultural fields, and tribal lands under section 4(d) of the Act.
(13) Whether any populations of the streaked horned lark should be considered separately for listing as a distinct population segment (DPS), and if so, the justification for how that population meets the criteria for a DPS under the Service's Policy Regarding the Recognition of Distinct Vertebrate Population Segments under the Endangered Species Act (61 FR 4722, February 7, 1996).
(14) Whether we could improve or modify our approach to designating critical habitat in any way to provide for greater public participation and understanding, or to better accommodate public concerns and comments.
Please note that submissions merely stating support for or opposition to the action under consideration without providing supporting information, although noted, will not be considered in making a determination, as section 4(b)(1)(A) of the Act directs that determinations as to whether any species is a threatened or endangered species must be made “solely on the basis of the best scientific and commercial data available.”
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We first identified the Taylor's checkerspot butterfly and the streaked horned lark as candidates for listing in the 2001 Notice of Review of Native Species that are Candidates for Listing as Endangered or Threatened (CNOR) (USFWS 2001). All candidate species are assigned listing priority numbers (LPN) that are based on the immediacy and magnitude of threats and taxonomic status. In 2001, both of these species were assigned an LPN of 6, which reflects threats of a high magnitude that are not considered imminent.
In 2004, based on new information, we determined that the Taylor's checkerspot butterfly faced imminent threats of a high magnitude and reassigned it an LPN of 3 (69 FR 24876; May 4, 2004). In 2006, the streaked horned lark was also reassigned an LPN of 3. During our review we determined that the continued loss of suitable lark habitat, risks to the wintering populations; and plans for development, hazing, and military training activities (71 FR 53755; September 12, 2006) were imminent threats to the subspecies. The candidate status for Taylor's checkerspot butterfly and streaked horned lark was most recently reaffirmed in the October 26, 2011, CNOR (USFWS 2011). The U.S. Fish and Wildlife Service (Service) completed action plans for Taylor's checkerspot butterfly and streaked horned lark
In 2001, we developed internal, discretionary candidate assessment documents for the Taylor's checkerspot butterfly and streaked horned lark. These candidate assessments were published in the
We discuss below only those topics directly relevant to the proposed listing of the Taylor's checkerspot butterfly and the streaked horned lark in this section of the proposed rule.
Taylor's checkerspot butterflies are medium-sized, colorfully marked butterflies with a checkerboard pattern on the upper (dorsal) side of the wings (Pyle 2002, p. 310). They are orange with black and yellowish (or white) spot bands, giving a checkered appearance (Pyle 1981, p. 607; Pyle 2002, p. 310). Taylor's checkerspot butterflies were historically known to occur in British Columbia, Washington, and Oregon, and current distribution has been reduced from over 80 locations rangewide to 14. Taylor's checkerspot butterflies produce one brood per year. They overwinter (diapause) in the fourth or fifth larval instar (developmental) phase and have a flight period as adults of 10 to 14 days, usually in May, although depending on local site and climatic conditions, the flight period begins in late April and extends into early July, as in Oregon, where the flight season may last for up to 45 days (Ross 2008, p. 2).
Taylor's checkerspot butterfly is a subspecies of Edith's checkerspot butterfly (
Taylor's checkerspot butterflies occupy open habitat dominated by
Female Taylor's checkerspot butterflies and their larvae utilize plants that contain defensive chemicals known as iridoid glycosides, which have been recognized to influence the selection of oviposition sites by adult nymphalid butterflies (butterflies in the family Nymphalidae) (Murphy
Historically, Taylor's checkerspot butterfly was likely distributed throughout grassland habitat found on prairies, shallow-soil balds, grassland bluffs, and grassland openings within a forested matrix in south Vancouver Island, northern Olympic Peninsula, the Puget Sound, and the Willamette Valley. The historical range and abundance of the species are not precisely known because extensive searches for Taylor's checkerspot butterfly did not occur until recently. Northwest prairies were formerly more common, larger, and interconnected, and would likely have supported a greater distribution and abundance of Taylor's checkerspot butterflies than prairie habitat does today. According to Pyle (2012,
Before recent declines over roughly the last 10 or 15 years the Taylor's checkerspot butterfly was known from an estimated 80 locations: 24 in British Columbia, 43 in Washington, and 13 in Oregon (Hinchliff 1996, p. 115; Shepard 2000, pp. 25-26; Vaughan and Black 2002, p. 6; Stinson 2005, pp. 93-96, 123-124). These sites included coastal and inland prairies on southern Vancouver Island and surrounding islands in the Straits of Georgia, British Columbia and the San Juan Island archipelago (Hinchliff 1996, p. 115; Pyle 2002, p. 311), as well as open prairies on post-glacial gravelly outwash and shallow-soil balds in Washington's Puget Trough (Potter 2010, p. 1), the north Olympic Peninsula (Holtrop 2010, p. 1), and grassland habitat within a forested matrix in Oregon's Willamette Valley (Benton County 2010, Appendix N, p. 5).
The 1949 field season summary for North American lepidoptera (Hopfinger 1949, p. 89) states that an abundant distribution of Taylor's checkerspot butterfly was known from the south Puget Sound prairies: “
Based on historical and current data, the distribution and abundance of Taylor's checkerspot butterflies have declined significantly rangewide with the majority of local extirpations occurring from approximately the mid-1990s in Canada (COSEWIC 2011, p. 15), 1999-2004 in south Puget Sound, and around 2006 at the Bald Hills location. Several new locations harboring Taylor's checkerspot butterflies have been rediscovered on historical sites on Washington Department of Natural Resources (WDNR) lands (USFWS 2004, pp. 3-4; USFWS 2007, p. 5) and have also been found at new locations on natural and manipulated balds within the upper
Nearly all localities for Taylor's checkerspot butterflies in British Columbia have been lost; the only location currently known from British Columbia was discovered in 2005 (COSEWIC 2011, p. iv). In Oregon, although many surveys have been conducted at a variety of historical and potential locations within the Willamette Valley, many of those have failed to detect the species; the number of locations occupied by Taylor's checkerspot butterflies has declined from 13 to 2 (Ross 2011,
Due to the limited distribution and few populations of Taylor's checkerspot butterfly, surveys for this species are quite thorough, generally consisting of a minimum of 3 days of visits during the flight period, and occasionally numbering up to 10 or 12 days of counts. Multiple days of counts during the annual flight period greatly increases the reliability of abundance data for butterflies, thus we believe the data on numbers of Taylor's checkerspot butterflies to be highly reliable.
After years of surveys (2001 through 2004) at historical population sites in British Columbia that failed to detect Taylor's checkerspot butterflies (COSEWIC 2011, pp. 15-16), a population was discovered on Denman Island in 2005. Denman Island is located approximately 106 miles (170 km) north of Victoria, British Columbia, along the eastern shores of Vancouver Island in the Straits of Georgia. Taylor's checkerspot butterfly records from British Columbia date from 1888 through 2011, when the last survey was conducted. Surveys are regularly conducted on Vancouver Island and other historical locations (Page
In Washington, surveys have been conducted annually for Taylor's checkerspot butterflies in currently and historically occupied sites. Surveys on south Puget Sound prairies have been conducted from 1997 through 2011 by the Washington Department of Fish and Wildlife (WDFW), WDNR, The Nature Conservancy of Washington (now the Center for Natural Lands Management), and personnel from the Wildlife Branch of Joint Base Lewis-McChord (JBLM; formerly known as Fort Lewis). In 1994, a report from Char and Boersma (1995) indicated the presence of Taylor's checkerspot butterflies on the 13th Division Prairie on JBLM; no additional locations have been reported since 1999, when a handful of Taylor's checkerspot butterflies were observed by WDFW (Hays
Four other populations in Thurston County (Glacial Heritage, Scatter Creek north and south units, and Rocky Prairie NAP) had Taylor's checkerspot butterflies present in 1997. No adult Taylor's checkerspot butterflies were observed during surveys conducted in 1998 and 1999 at these locations (Hays
Four historical locales for Taylor's checkerspot butterflies were permanently lost in the south Puget Sound region to development (Dupont, JBLM Training Area 7S, Spanaway, and Lakewood in Pierce County) or conversion to agriculture (Rock Prairie in Thurston County) (Stinson 2005, pp. 93-96). In addition, several older Washington specimens are labeled with general or imprecise locality names on their collection labels (e.g., Olympia 1893; Tenino 1929; Shelton 1971, Dungeness 1999) (Stinson 2005, pp. 94-95). Some of these site names may refer to unknown or currently occupied locales but due to their imprecise nature, the true location of these potential populations has not been determined.
Surveys of 15 prairies within the south Puget Sound landscape in 2001 and 2002 located Taylor's checkerspot butterflies on only 4 sites in Thurston and Pierce Counties (Stinson 2005, pp. 93-96). Three of the four sites were found in the Bald Hill landscape in Southeast Thurston County. Taylor's checkerspot butterflies were documented at the Bald Hills through 2007, but there have been no detections since, despite regular and thorough surveying from 2001 through 2011 (Potter 2011, p. 3). This number has declined substantially in recent years as habitat has become increasingly shaded and modified by encroaching trees, nonnative grasses, and the invasive, nonnative shrub Scot's broom (
The 91st Division Prairie is located on JBLM on the eastern edge of the approximately 6,000 acre (2,400 ha) prairie. The largest current populations of Taylor's checkerspot butterfly within the south Puget Sound have been observed here, and have served as the source populations for the collection of larvae for captive breeding to support translocation efforts. Several small, discrete patches of habitat are occupied by Taylor's checkerspot butterflies. The close proximity of these patches indicates that a relatively robust population (more than 1,000 butterflies surveyed in a single day in 2006) is likely present at JBLM.
In the course of conducting surveys for another rare grassland-associated butterfly found in Washington, the island marble (
Several historical sites with potentially suitable habitat were surveyed on the north Olympic Peninsula (Clallam County) during spring 2003. Taylor's checkerspot butterfly was found to occupy five locations in this geographic area in 2003. At one historical site near the mouth of the Dungeness River, only a few individuals were detected. However, no Taylor's checkerspot butterflies were detected at this location during surveys from 2005 through 2009 (McMillan 2007, pers. comm.; Potter 2012, pers. comm.). The other four populations were found on grassy openings on shallow-soiled bald habitat west of the Elwha River. Two of these sites were estimated to support at least 50 to 100 adult Taylor's checkerspot butterflies (Dan Kelly Ridge and Eden Valley), and just a few individuals were found at the two other bald sites (Striped Peak and Highway 112) (Hays 2011, p. 1). Subsequent surveys at the latter two sites, Striped Peak and Highway 112, from 2004-2011, have failed to relocate or detect any Taylor's checkerspot butterflies.
In 2006 a population was discovered near the town of Sequim. Taylor's checkerspot butterflies have since been detected annually at this location from 2006-2011 (Hays 2009, pers. comm.; Hays 2011, p. 29). At this site, Taylor's checkerspot butterflies inhabit approximately 5 ac (2 ha) of estuarine, deflation plain (or back beach), a road with restricted use, and farm-edge habitat. In 2010, a maximum count of 568 Taylor's checkerspot butterflies was recorded on a single day (April 3, 2010); normally peak daily counts from this location range from 50 to 240 individuals (Hays 2011, p. 29).
Since 2007, three new Taylor's checkerspot butterfly populations have been found in Clallam County on Olympic National Forest lands. All three sites are located in the Dungeness River watershed: Bear Mountain, Three O'Clock Ridge, and Upper Dungeness (Holtrop 2009, p. 2). The Forest Service and WDFW are currently monitoring butterfly numbers at these sites annually. As of 2012, a total of six occupied sites are known from Clallam County: Sequim, Eden Valley, Bear Mountain, Three O'Clock Ridge, and Upper Dungeness.
All of the 13 historical locales within the Willamette Valley of western Oregon have been surveyed regularly by local lepidopterists (McCorkle 2008, pers. comm.; Ross 2005: Stinson 2005, p. 124; Benton County 2010, p. 13; Potter 2012, pers. comm.). Taylor's checkerspot butterflies were formerly reported to exist in large numbers (“swarms on the meadows beside Oak Creek”) on the upland prairies of the Willamette Valley in Lane, Benton, and Polk Counties (Dornfeld 1980, p. 73). Now only remnant populations exist in Oregon. In 1999, Taylor's checkerspot butterflies were discovered along the Bonneville Power Administration (BPA) right-of-way corridor in an area known as Fitton Green in Benton County. In 2004 surveys for Taylor's checkerspot butterfly were expanded in the Willamette Valley where a second population was discovered on grassland openings within the Beazell Memorial Forest in Benton County. These two locations for Taylor's checkerspot butterfly are currently the only occupied patches known from Oregon.
There is little historical information on population estimates for Taylor's checkerspot butterflies and the survey techniques used for monitoring have differed over time. Early surveys at most locations were done using Pollard transect sampling methodology. Prior to implementing distance sampling as the accepted survey method for Taylor's checkerspot butterflies, population sizes were determined by tallying the number of all butterflies observed in a day and this was expressed as the maximum day count for a population at a specific site. During the survey season from 2007 through 2011, WDFW implemented distance sampling methods to estimate abundance at the site in Washington on JBLM. Distance sampling involves establishing permanent transects over a proportion of the survey area to determine the probability of detecting the butterfly. This number is used to calculate abundance (Marques 2009). Because Taylor's checkerspot butterfly population numbers change daily due to emergence and mortality of individuals, density estimates were computed by survey date (Linders and Olson 2011, p. 11). Although the sampling methods have changed over the years, we believe they are useful in providing a general estimate of population trend information. Additionally, since 2007, a consistent survey method for distance sampling has been implemented throughout most of the range, providing reliable annual information.
The recently discovered population in British Columbia (BC) was confirmed by the invertebrate specialist for the BC Ministry of the Environment (Heron 2008, pers. comm.). A total of 12 adults were observed on Denman Island during 2005 (Table 1) (Page
In Washington State, more than 43 historical locales were documented as having Taylor's checkerspot butterfly populations. In 2012, there are only 11 documented populations, with only 1 of the sites harboring more than 1,000 individuals at any time and the majority of known sites yielding daily counts of fewer than 100 individual butterflies. These locations are as follows: Striped Peak, Highway 112, Sequim, Eden Valley, Dan Kelly Ridge, Bear Mountain, Three O'Clock Ridge, Upper Dungeness, 91st Division Prairie on JBLM, Scatter Creek Wildlife Area, and the Bald Hills.
Taylor's checkerspot butterflies have been surveyed annually on the northeastern Olympic peninsula since 2003. Striped Peak, located on WNDR lands, supported Taylor's checkerspot butterflies as early as 1985. Between 2003 and 2005, only a few adult butterflies were observed by WDFW personnel at Striped Peak and a second site known as Highway 112. No butterflies have been observed at the Striped Peak or Highway 112 locations since that time (McMillan 2009, pers. comm.; Hays 2011, p. 1). Both sites are being encroached by
In 2006, at the Sequim population, as many as 100 butterflies were detected on a single day; however, on many days fewer butterflies were observed (McMillan 2007, pers. comm.). In spring 2007, researchers detected 100 to 200 butterflies on peak days. Both larvae and adults were present at this site in
On Dan Kelly Ridge, as many as 50 butterflies were detected during surveys on a single day in 2006. This is a large, linear site with a ridgeline road greater than 2 miles (3.2 km) long; grassland habitat with larval food plants are found along the road margins and in forest openings on steep south facing slopes where shallow-soil balds support Taylor's checkerspot butterflies. Between 2007 and 2010, maximum daily counts ranged from 60 to 100 butterflies. Surveys were not conducted at this site in 2011.
In 2007, on Three O'Clock Ridge in the upper Dungeness watershed of Olympic National Forest, a small number (two) of Taylor's checkerspot butterflies were first detected (Holtrop 2010, p. 1). This site was surveyed in 2008 by Forest Service and WDFW personnel who detected 12 adult butterflies (Holtrop 2010, p. 1). In 2009, approximately 300 ac (121 ha) of suitable habitat were surveyed (Holtrop 2010, p. 5) and two new populations were discovered, at Upper Dungeness and Bear Mountain. Maximum single day counts ranged from 40 to 69 butterflies at the Three O'Clock Ridge, Upper Dungeness, and Bear Mountain. These sites have supported Taylor's checkerspot butterflies consistently since their discovery (Holtrop 2010, p. 13).
The largest known population of Taylor's checkerspot butterfly is located on the 91st Division Prairie at JBLM where a high complement of larval and nectar host plants exist. During the 2005 and 2006 flight seasons (Combs 2005, p. 8; Wolford 2006, pp. 18-20), more than 1,000 individuals were detected on maximum single day counts and hundreds of individuals were observed throughout the flight season (Combs 2005, p. 8; Wolford 2006, pp. 18 and 20). Surveys in spring 2007 detected slightly lower numbers despite the high survey effort. In 2007, the single-day maximum count for Taylor's checkerspot butterflies was 637 (Wolford
During 10 surveys conducted in the spring of 2009 at 91st Division Prairie, 77 individual butterflies were counted as a maximum daily count (Linders 2009a, entire; Thomas 2009b, pers. obs.). Spring counts in 2009, 2010, and in 2011 showed a general trend of increasing observations at this site, apparently because of a rebound in larval food plants along the roads margins used by military training vehicles, and from repeated and frequent fires caused by military training exercises. Oviposition on larval host plants (narrow-leaf plantain) near road margins was observed at all known Taylor's checkerspot butterfly locations in Washington State (Severns and Grosboll 2011, p. 66).
Experimental introductions of Taylor's checkerspot butterflies have been attempted in the south Puget Sound region. In 2006, Taylor's checkerspot butterfly larvae were placed out at four locations in Thurston and Pierce County: (1) In March 2006, larvae were released at Glacial Heritage Preserve, a Thurston County park; (2) in June 2006, larvae were placed at two locations on JBLM (Training Area 7 South (TA 7S) and 13th Division Prairie); and (3) at the Scatter Creek Wildlife area in Thurston County. None of these initial test releases resulted in observations of adult butterflies at these locations during the subsequent flight season (Linders 2007, p. vi). A subsequent release of 199 larvae in March 2007 at Scatter Creek Wildlife Area resulted in 11 Taylor's checkerspot butterfly observations there in May 2007 (Linders 2007, p. 18).
Based on this early success with captive rearing of larvae, an additional 340 larvae were placed at Scatter Creek Wildlife Area in March 2008. A peak daily count of 16 adult Taylor's checkerspot butterflies were documented at this location in 2008 (Linders 2011c). In 2009, Linders released approximately 2,250 post-diapause larvae onto suitable habitat at Scatter Creek Wildlife Areas and 13th Division Prairie on JBLM, which resulted in 48 observations of adult butterflies and a peak day count of 36 adults at Scatter Creek South, two adults at Scatter Creek North and 1 individual at 13th Division Prairie on JBLM (Linders 2010,
Surveys of private property and WDNR-managed land in the Bald Hill area in 2006 detected only a few individual Taylor's checkerspot butterflies during any given survey day on each of the primary balds. Reports and personal observation indicate that the density and composition of larval host plants have declined at the Bald Hills area and portions of some of the balds have been invaded by Douglas-fir and other shrub species, including Scot's broom, thus reducing the area and suitability of habitat (Potter 2011, p. 1). Taylor's checkerspot butterflies have not been detected in the Bald Hills area since 2007, despite intensive survey efforts in 2008 and 2011 (Potter 2011, p. 1). This population of Taylor's checkerspot butterfly is presumed to be extirpated.
In Oregon, Taylor's checkerspot butterflies are known from two locations in the Willamette Valley of Benton County, Beazell Memorial Park (BMP) and Fitton Green Natural Area. Annually, population estimates at these two sites have varied from greater than 1,200 butterflies at Fitton Green in 2005 to as few as 150 butterflies in 2006 at BMP (Ross, 2010, pp. 4, 6; Ross 2011,
The streaked horned lark is endemic to the Pacific Northwest (British Columbia, Washington, and Oregon; Altman 2011, p. 196) and is a subspecies of the wide-ranging horned lark (
The horned lark is found throughout the northern hemisphere (Beason 1995, p. 1); it is the only true lark (Family Alaudidae, Order Passeriformes) native to North America (Beason 1995, p. 1). There are 42 subspecies of horned lark worldwide (Clements
Streaked horned larks were closely related to the California samples and only distantly related to the three closest localities (alpine Washington, eastern Washington, and Oregon); only one of the eastern Washington individuals shared the streaked horned lark haplotype, indicating a single example of gene flow from western Washington to eastern Washington (Drovetski
The lack of mitochondrial DNA (mtDNA) diversity exhibited by streaked horned larks is consistent with a population bottleneck (Drovetski
Horned larks forage on the ground in low vegetation or on bare ground (Beason 1995, p. 6); adults feed mainly on grass and weed seeds, but feed insects to their young (Beason 1995, p. 6). A study of winter diet selection found that streaked horned larks in the Willamette Valley eat seeds of introduced weedy grasses and forbs, focusing on the seed source that is most abundant (Moore 2008b, p. 9). In this Willamette Valley study, a variety of grasses (
Horned larks form pairs in the spring (Beason 1995, p. 11). Altman (1999, p. 11) used a small sample (n=3) of streaked horned lark territories in the Willamette Valley to give a mean territory size of 1.9 acres (0.77 ha) with a range of 1.5 to 2.5 acres (0.61 to 1.0 ha). Horned larks create nests in shallow depressions in the ground and line them with soft vegetation (Beason 1995, p. 12). Female horned larks select the nest site and construct the nest without help from the male (Beason 1995, p. 12). Streaked horned larks establish their nests in areas of extensive bare ground, and nests are placed adjacent to clumps of bunchgrass (Pearson and Hopey 2004, pp. 1-2). In the Willamette Valley, nests are almost always placed on the north side of a clump of vegetation or another object such as root balls or soil clumps (Moore and Kotaich 2010, p. 18). Studies from Washington sites (the open coast, Puget lowlands and the Columbia River islands) have found strong natal fidelity to nesting sites—that is, streaked horned larks return each year to the place they were born (Pearson
The nesting season for streaked horned larks begins in mid-April and ends in the early part of August (Pearson and Hopey 2004, p. 11; Moore 2011, p. 32). Clutches range from 1 to 5 eggs, with a mean of 3 eggs (Pearson and Hopey 2004, p. 12). After the first nesting attempt in April, streaked horned larks will often re-nest in late June or early July (Pearson and Hopey 2004, p. 11). Young streaked horned larks leave the nest by the end of the first week after hatching, and are cared for by the parents until they are about 4 weeks old when they become independent (Beason 1995, p. 15).
Nest success studies (i.e., the proportion of nests that result in at least one fledged chick) in streaked horned larks report highly variable results. Nest success on the Puget lowlands of Washington is low, with only 28 percent
Historically, nesting habitat was found on grasslands, estuaries, and sandy beaches in British Columbia, in dune habitats along the coast of Washington, in western Washington and western Oregon prairies, and on the sandy beaches and spits along the Columbia and Willamette Rivers. Today, the streaked horned lark nests in a broad range of habitats, including native prairies, coastal dunes, fallow and active agricultural fields, wetland mudflats, sparsely-vegetated edges of grass fields, recently planted Christmas tree farms with extensive bare ground, moderately- to heavily-grazed pastures, gravel roads or gravel shoulders of lightly-traveled roads, airports, and dredge deposition sites in the lower Columbia River (Altman 1999, p. 18; Pearson and Altman 2005, p. 5; Pearson and Hopey 2005, p. 15; Moore 2008, pp. 9-10, 12-14, 16). Wintering streaked horned larks use habitats that are very similar to breeding habitats (Pearson
Habitat used by larks is generally flat with substantial areas of bare ground and sparse low-stature vegetation primarily comprised of grasses and forbs (Pearson and Hopey 2005, p. 27). Suitable habitat is generally 16-17 percent bare ground, and may be even more open at sites selected for nesting (Altman 1999, p.18; Pearson and Hopey 2005, p. 27). Vegetation height is generally less than 13 in (33 cm) (Altman 1999, p.18; Pearson and Hopey 2005, p. 27). Larks eat a wide variety of seeds and insects (Beason 1995, p. 6), and appear to select habitats based on the structure of the vegetation rather than the presence of any specific food plants (Moore 2008, p. 19). A key attribute of habitat used by larks is open landscape context. Our data indicate that sites used by larks are generally found in open (i.e., flat, treeless) landscapes of 300 acres (120 ha) or more (Converse
Although streaked horned larks use a wide variety of habitats, populations are vulnerable because the habitats used are often ephemeral or subject to frequent human disturbance. Ephemeral habitats include bare ground in agricultural fields and wetland mudflats; habitats subject to frequent human disturbance include mowed fields at airports, managed road margins, agricultural crop fields, and disposal sites for dredge material (Altman 1999, p. 19).
The streaked horned lark's breeding range historically extended from southern British Columbia, Canada, south through the Puget lowlands and outer coast of Washington, along the lower Columbia River, through the Willamette Valley, the Oregon coast and into the Umpqua and Rogue River Valleys of southwestern Oregon.
There are a few historical records of streaked horned larks on the outer coast of Washington near Lake Quinault, the Quinault River and the Humptulips River in the 1890s (Jewett
There are scattered records of streaked horned larks in the northern Puget Trough, including sightings in Skagit and Whatcom Counties in the mid-20th