California Partners in Flight

Lark Sparrow (Chondestes grammacus)
Oak Woodland Species Account, supporting the Oak Woodlands Bird Conservation Plan

Prepared by: Diana Humple, Point Reyes Bird Observatory, 4990 Shoreline Highway, Stinson Beach CA 94970, dianahumple at prbo dot org

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references

Section 1: Species account outline.

SPECIES: Lark Sparrow (Chondestes grammacus)

SUBSPECIES STATUS: The Western Lark Sparrow (C. g. strigatus) breeds and winters in California.

MANAGEMENT STATUS: No special status. Protected under the Migratory Bird Act.

Historical references:
Grinnell and Miller (1944) described the range of this species as breeding chiefly in interior valleys, plains, and low mountains west of Sierra Nevadas and Cascades, and breeding to some degree in all sections of state except the deserts of the southeast.

Current breeding distribution:

• Overview:

Widespread breeder over much of the state on the west side of the Cascade/Sierra Nevada Ranges, south of the Klamath Mountain region, and west of the southeastern deserts. Breed in Great Basin area (Small 1994). A common or fairly common resident in lowlands and foothills throughout the state (Zeiner et al. 1990)

Point count (singing individual encountered on 2 or more different days of census-at least one week apart):

• Klamath Bioregion:

Detected in Brewer’s oak forest, Mendocino National Forest (Gardali and Geupel 1997).
Detected on the East Park Preserve, coast range foothills, Colusa County (PRBO data 1997-1999).

• Sacramento Valley Bioregion:

Detected using orchards with cover crops (PRBO data 1999, King 2000).
Detected on Stony Creek Preserve in riparian habitat (King and Geupel 1998).

• Bay/Delta Bioregion:

Detected locally within the Marin Municipal Water District in Marin County (Holmes et al. 1998).
Detected at the Cosumnes Preserve (DiGaudio and Geupel 1998).

Mist netting (female with brood patch, female with eggs in oviduct, juvenile with no skull ossification before 1 August):

• San Joaquin Valley Bioregion: very few (n=4) birds captured during breeding over a 3 year study; only adult captured was a male with a cloacal protuberance (PRBO data).

Nest searching:

• Bay/Delta Bioregion:

Nest found at the Cosumnes Preserve (PRBO data).

Spot mapping:

• Sacramento Valley Bioregion (PRBO data 1998).

Area search:

Breeding Bird Atlas:

• Klamath Bioregion:

Northwestern California Birds: Lark Sparrow is a local, uncommon breeder in this part of the state, mostly in the southwestern portion of the region (Mendocino County) (Harris 1991).

• Bay/Delta Bioregion:

Marin County BBA: Widespread breeders in central Marin county, found in grasslands that generally have trees, bushes, or rock outcrops (Shuford 1993).

Sonoma county BBA: year-round resident. Grinnell and Miller (1944) had birds present around Sebastopol and Cazadero, but during the Atlas period no Lark Sparrows were recorded there (Burridge 1995).

• Central Coast Bioregion:

Monterey County BBA: common permanent resident (Roberson an Tenney 1993).

• South Coast Bioregion:

Birds of Orange County: fairly common resident in open coastal sage scrub and grasslands (Hamilton and Willick 1996).

Birds of Santa Barbara County: breed in grassland, especially oak savannah, mostly in the foothills and grassy areas along the northern coastal region (Lehman 1994).

ECOLOGY:

Departure date from breeding grounds: nonresidential breeders in the northeastern part of the state (Modoc Bioregion) presumably migrate around late September.

Extent of wintering in CA:

In winter, Lark Sparrows found north at least as far as Tehama County, and south through the Central Valley and coastal areas to Mexico. East of Sierra Nevadas, they winter from San Bernadino County south through Imperial County, and uncommonly east to the Colorado River (Grinnell and Miller 1944).
They are rare winterers in the Klamath Bioregion of the northwestern portion of state (Harris 1991).
During fall and winter, there is an increase in number of individuals in southern California, with the exception of the mountainous areas, corresponding with departure from northeastern portion of state. There is also likely an influx of birds from outside California into the state during the fall and winter (Small 1994).
Wintering birds are also found on the western edges of the southeastern deserts, where they do not breed; also fairly common winter visitor on Santa Cruz Island, and uncommon winterer on other Channel Islands (Small 1994).

Migration stop-over needs/characteristics:
Habitat use: Some anecdotal evidence suggests habitat use during migration to be similar to habitat use by the species during the breeding season (Martin and Parrish 2000).

Nest type: open-cup

Foraging strategy: Forage on the ground or at least low in vegetation, even if there are higher trees or shrubs that they use for perching (Grinnell and Miller 1944).

Post breeding social behavior (mixed species flocks, or simply migrate away?): In migration and winter, occur generally of flocks consisting of entirely or primarily other Lark Sparrows (Rising 1996).

Clutch size: 4-5 (3-6)
Nestling period: 9-10 days.
Number of broods: Normally one, occasionally two (Martin and Parrish 2000).

Major food items (by season): grains and leguminous plants are most important; among insects, grasshoppers are a favorite (G&M 1944). In a study in New Mexico its diet was found to consist of 27% insects and 73% seeds; half of its animal food is grasshoppers. In some areas it is helps check locust invasions, and in other areas eats alfalfa weevils (Bailey 1928).

Wintering ground needs and distribution:
In winter can be found in agricultural areas, oak woodland, chaparral, arid grasslands, semi-desert, and sometimes even in suburban gardens, lawns and parks (Small 1994, Rising 1996).

BREEDING HABITAT AND NEST SITE CHARACTERISTICS:

Overview of breeding habitat: (e.g. oak woodland vs. oak savannah, age of stand, dominant species, plant species diversity, structural diversity/variability).

Described by Grinnell and Miller (1944) as breeding in "open terrain with scattered bushes and trees such that there is opportunity to forage on the ground and yet utilize elevated places for viewpoints and retreats." Habitats in California that provide such a combination of needs, and in which they are found breeding, include oak savannah, open chaparral, semi-desert, mesquite, pinyon-juniper, some orchards, open cottonwood riparian woodland, grassland bordered by trees or bushes, and ponderosa pine interspersed with bunch grasses (Grinnell and Miller 1944, Roberson and Tenney 1993, Small 1994, Rising 1996).

Nest Site:

Substrate (species): usually nest on ground, sometimes in low shrub or tree. Nest is often placed at the base of bunch grass, small cactus, forb, or shrub (Baepler 1968, Rising 1996, PRBO data 1995-1997); once observed nesting in a cavity of a dead willow (Newman 1970). Trees used as substrates include live oak, cottonwood, sycamore, and mesquite (Rising 1996).
Height of nest: usually on the ground, sometimes up to 7 ft, rarely up to 25 ft

Vegetation surrounding the nest (Importance of each category may differ by species):

Canopy cover:

• Other sites: in pinyon-juniper habitat, Lark Sparrow abundance decreased as tree density increased (Martin and Parrish 2000).

• Other sites: in shrub-steppe habitat in Oregon, points where Lark Sparrows occurred had significantly less green ground cover, less grass, and more bare ground than points where they were absent. Lark Sparrow abundance was negatively correlated with perennial grass cover and positively correlated with bare ground (Holmes and Geupel 1998).

Landscape factors:

Elevation: sea level to about 6000 feet (Small 1994)

Disturbance (natural or managed): (e.g. floods, fires, logging): In a study at the Sierra Foothill Research Extension Center in California, Lark Sparrows were shown to increase slightly after firewood harvest (Aigner et al. 1998), which is concordant with their preference for open ground and grassland. In a study of prescribed burns in honey-mesquite/tobosagrass habitat in Texas, breeding densities of Lark Sparrows were highest in the most recent burns, and decreased with increased littler buildup as well as waning grass production. It was suggested that such prescribed burns in this habitat would in general benefit Lark Sparrows, provided they are done prior to the onset of breeding. However "hot" fires may have negative effects as they can reduce the number of potential nest sites, both shrubs and grass (Renwald 1977).

SPECIAL FACTORS: Factors influencing a species occurrence and viability.

Brood parasitisim: Frequent host species (Martin and Parrish 2000).

Other sites:

In Oklahoma, 15 of 33 nests (45.5%) were parasitized. 3 of these nests fledged cowbird young. The percent of host young that were successfully fledged was higher in unparasitized nests than parasitized nests. This study revealed parasitism rates higher than those previously recorded for this species, which has at times been defined as an uncommon cowbird host. This is perhaps a result of the extirpation or absence of the Bell’s Vireo on this study area, a previously common species there which is also a frequent cowbird host. Evidence from this study suggests that later broods (be they second attempts or second broods) encounter little or no parasitism (Newman 1970).
Pesticide use: "injurious" insects constitute 25% of their food matter, including species such as grasshoppers, locusts, and alfalfa weevils (Bailey 1928). Thus the Lark Sparrow could be valuable in the control of agricultural pests, but this same feature also makes them vulnerable to pesticide use.
Predators: Low and ground nests vulnerable to predation.
Exotic species invasion/encroachment: In some areas, Lark Sparrows no longer nest where habitat in which they formerly bred has been converted due to loss of native grassland and shrubs and replacement with invasive exotic grasses (Martin and Parrish 2000).
Other: In the Sacramento Valley PRBO found Lark Sparrows using orchards with cover crops, while they were absent in conventional orchards (King 2000). In the lower Colorado River Valley of Arizona (and possibly California), Lark Sparrows were found nesting exclusively in orchards and cultivated vegetation by farmhouses, in areas in which Lark Sparrows previously did not breed before population and agricultural expansion into the area (Rosenberg 1991).

Because it is a ground nester, Lark Sparrow is vulnerable to such disturances as grazing, burning, and off-road vehicles (Neotropical migrant bird reference book 1994) POPULATION TREND: http://www.mbr.nbs.gov/bbs/bbs.html

• In California, Lark Sparrows showed no significant trend during the 1966-1998 study period. However, a significant negative trend (p<0.01) was found for Lark Sparrows in the California Foothills during the 1966-1979 period, and a nearly significant trend (p=0.08) during the 1980-1998 period for this region. A significant negative trend was observed over the 1966-1979 period in the southern California grassland region, but the number of detections was likely too low for this to be meaningful (Sauer et al. 1999).

• Lark Sparrows have shown a significant negative nationwide trend (Sauer et al. 1999). However, this is likely due to the changes in eastern populations. Lark Sparrows colonized the eastern portion of the United States in the 19^th century, but have since declined there and are only rare and local today. The colonization is believed to have resulted from the increase in suitable habitat provided by massive deforestation, and the decline observed today is probably a result of the return of second-growth forest on land that was previously farmland (Rising 1996, Martin and Parrish 2000).

• Have recently begun nesting in orchards in parts of southern California where Lark Sparrows were not previously known to breed (Garrett and Dunn 1981).

• Most likely much Lark Sparrow habitat has been lost as grassland has been converted to agriculture (Roberson an Tenney 1993).

• In Monterey County, where the Lark Sparrow is a common permanent resident, there is some concern about the absence of Lark Sparrows in some seemingly suitable habitat in certain areas of the county, notably near human development. Although there is no historical data for these regions, it is suspected that there has been a decline of this species there (Roberson an Tenney 1993).

• Grinnell and Miller (1944) had birds present around Sebastopol and Cazadero in Sonoma County, but during the Atlas period no Lark Sparrows were recorded there (Burridge 1995).

DEMOGRAPHICS:

Proportional nest success (n=19) over 3 years in shrub-steppe habitat in Oregon was 32%; Mayfield estimates of nest survivorship (n=18) was 30% (Holmes and Geupel 1998).

In Oklahoma, nest success was significantly greater for nests built above ground (44.5%) than those built on the ground (23.7%) (Newman 1970).

MANAGEMENT ISSUES: Fire suppression may allow grass to grow into dense stands, converting grassland into habitat unsuitable for Lark Sparrows (Martin and Parrish 2000). Grazed areas appear to be preferred by this species (for review see Martin and Parrish 2000). In some areas, Lark Sparrows no longer nest where habitat in which they formerly bred has been converted due to loss of native grassland and shrubs and replacement with invasive exotic grasses (Martin and Parrish 2000). Although fire may be favorable for this species in some cases, if the burn is such that all shrubs are killed the area is likely to not be used by breeding Lark Sparrows (Renwald 1977).

MONITORING METHODS AND RESEARCH NEEDS: Recommend methods that will address immediate needs as well as those most appropriate to monitor how effective the proposed management recommendations will be.

It is believed that the Lark Sparrow's preference for what are frequently edge habitats has caused this species to basically have fallen within the cracks and thus be excluded from research and monitoring. In fact currently no definitive studies have been done on the Lark Sparrow, and it is almost alarming how little recent research has been done addressing the life history and needs of this species (Martin and Parrish 2000).

Section 2: Action plan summary. Summarize the above information into concise statements under each section.

STATUS (from subspecies, trend, local extirpations, state and federal lists, etc.)

• No special status.

• Lark Sparrows showed no trend in California during the 1966-1998 study period. However, a significant negative trend (p<0.01) was found for Lark Sparrows in the California Foothills during the 1966-1979 period, and a nearly significant trend (p=0.08) during the 1980-1998 period for the same region. A significant negative trend was observed over the 1966-1979 period in the southern California grassland region, but the number of detections was likely too low for this to be meaningful (Sauer et al. 1999).

• Some local population changes: Have recently begun nesting in orchards in parts of southern California where Lark Sparrows were not previously known to breed (Garrett and Dunn 1981). Most likely much Lark Sparrow habitat in California has been lost as grassland has been converted to agriculture (Roberson and Tenney 1993). In Monterey County, where the Lark Sparrow is a common permanent resident, there is some concern about the absence of Lark Sparrows in some seemingly suitable habitat in certain areas of the county, notably near human development. Although there is no historical data for these regions, it is suspected that there has been a decline of this species there (Roberson an Tenney 1993). Another local change: Grinnell and Miller (1944) had birds present around Sebastopol and Cazadero in Sonoma County, but during the Atlas period no Lark Sparrows were recorded there (Burridge 1995).

HABITAT NEEDS (e.g., elevation, patch size, breeding habitat characteristics, disturbance)

Described by Grinnell and Miller (1944) as breeding in "open terrain with scattered bushes and trees such that there is opportunity to forage on the ground and yet utilize elevated places for viewpoints and retreats", and sometimes nesting substrates. Habitats in California that provide such a combination of needs, and in which they are found breeding, include oak savannah, open chaparral, semi-desert, mesquite, pinyon-juniper, some orchards, open cottonwood riparian woodland, grassland bordered by trees or bushes, and ponderosa pine interspersed with bunch grasses (Grinnell and Miller 1944, Roberson and Tenney 1993, Small 1994, Rising 1996). Fragmentation does not seem to be an issue for this species. Are sometimes described as an edge species.

CONCERNS (e.g., productivity, brood parasitism, habitat loss, lack of information, wintering distribution, pesticide use)

Uncommon to common cowbird host. However, Lark Sparrows have so rarely been the focus of avian studies that little data on them actually exists on this and other subjects for almost all regions. Conversion of oak savannah and grassland to agriculture may be a problem; it is unknown what affects conversion to vineyards is having on this species, and this should be further explored. Inhibition of fire events may result in loss of appropriate habitat. Hot fires may also be a problem when shrubs and trees are destroyed. Pesticide use may definitely be a problem, as much of their diet includes pest insects such as grasshoppers, locusts, and alfalfa weevils. Despite the affinity of Lark Sparrows for grazed oak woodlands, cattle grazing prevents oak regeneration and in the long run this is not an appropriate management tool for Lark Sparrows in this habitat.

OBJECTIVES (e.g., increase distribution, identify healthy breeding populations, increase available habitat, guide restoration efforts to benefit species)

Identify healthy breeding populations and examine productivity and effects of cowbird parasitism.

Protect remaining habitat used by Lark Sparrows and associated species.

Guide restoration efforts in grassland and oak woodland in ways which take Lark Sparrows into account.

Examine effects of conversion of oak woodland into vineyards on Lark Sparrows.

Increase use of cover crops in orchards as opposed to conventional orchards and conventional pest control.

ACTION (e.g., acquire and restore habitat, specific management and restoration recommendations, specific research and monitoring needs, specific land protection recommendations)

Implement large-scale inventory of oak woodland (being certain to include oak savannah) habitat in California.

From this inventory, identify potential source populations. These populations can be further studied in order to determine productivity and parasitism effects; this will include other species besides Lark Sparrows. The lack of such data on Lark Sparrows anywhere, and especially in California, is alarming and the need to collect even baseline data of this species in habitats other than shrub-steppe (where Lark Sparrows have been studied more extensively, outside of California) is clear.

Encourage landowners of remaining oak woodland to protect and, if necessary, restore the habitat. This includes working with vineyards and convincing them to retain some oak woodland as opposed to total conversion into vineyard. This includes not only keeping some oak trees, but also keeping areas of understory (grasses, forbs and shrubs) undisturbed.

Guide restoration efforts in grassland and oak woodland in ways which take Lark Sparrows into account. Due to its negative and long-term effects on oak regeneration, cattle grazing is not likely an appropriate management tool for Lark Sparrows in oak savannah, despite their apparent affinity for grazed grasslands. Instead, examine and implement more appropriate methods. In some habitats this may include encouraging land owners to do prescribed burns, but ones that are not too hot and not during the breeding season, being sure to not eliminate existing shrubs and/or trees from grasslands or meadows. In areas where efforts are being made to eliminate cattle grazing, in order to allow the regeneration of oaks, burning may be critical if managing for this species. However, as in all cases, more study is needed on a region by region level to determine what effects burning will have on the exotic grass problem.

Encourage orchard owners to use cover crops instead of conventional, plowed orchards with conventional pest control. Do this by extending our information to as many orchard growers as possible.

SCIENTIFIC REFERENCES:

Aigner, P.A., W.M. Block and M.L. Morrison. 1998. Effect of firewood harvesting on birds in a California oak-pine woodland. J. Wildl. Manage. 62(2): 485-496.

Bailey, F. M. 1928. In Baepler, D. H. 1949, Lark Sparrow, p. 895. in Life histories of North American cardinals, grosbeaks, buntings, towhees, finches, sparrows and allies (A.C. Bent, Ed.). U.S. National Museum Bulletin No. 196.

Baepler, D. H. 1949. Lark Sparrow, pp. 886-902. in Life histories of North American cardinals, grosbeaks, buntings, towhees, finches, sparrows and allies (A.C. Bent, Ed.). U.S. National Museum Bulletin No. 196.

Burridge, B., Editor. 1995. Sonoma County Breeding Bird Atlas. Madrone Audubon Society.

DiGaudio, R. and G.R. Geupel. 1998. Songbird monitoring on the Cosumnes River Preserve: progress report of the 1998 field season. PRBO report to the Cosumnes River Preserve (???).

Gardali, T. and G. R. Geupel. 1997. Songbird census in the Mendocino National Forest: results from the 1997 field season. PRBO report to the Mendocino National Forest.

Garrett, K. and J. Dunn. 1981. Birds of southern California: status and distribution. p. 290-291 Artisan Press, Los Angeles, California.

Grinnell, J. and A.H. Miller. 1944. The distribution of the birds of California, pp.367-369. Pacific Coast Avifauna no. 27.

Hamilton, R.A. and D.R. Willick. 1996. The birds of Orange County: status and distribution. Sea and Sage Press, Sea and Sage Audubon Society, Irvine, CA.

Harris, S. W. 1991. Northwestern California birds. By Stanley W. Harris.

Holmes, A. L. and G. R. Geupel. 1998. Avian population studies at Naval Weapons Systems Training Facility Boardman, Oregon. PRBO final report to the Department of Navy and Oregon Department of Fish and Wildlife.

Holmes, A. L., G. R. Geupel, and G. Ballard. 1998. Distribution, abundance, and diversity of songbirds on watershed lands managed by the Marin Municipal Water District. PRBO final report to the Marin Municpal Water District.

King, A. 2000. Working with prune growers in the Sacramento Valley. in Flight Log: Newsletter of the California Partners in Flight. Issue No. 9, winter 1999-2000.

Lehman, P.E. 1994. Birds of Santa Barbara County. Vertebrate Museum Univ. of Cal, Santa Barbara.

Martin, J. W. and J. R. Parrish. 2000. Lark sparrow (Chondestes grammacus). In The Birds of North America, No.--- (A. Poole and F. Gill, Eds.). The Birds of North America, Philadelphia, PA.

Neotropical Migratory Bird Reference Book Vol. 1. USDA Forest Service, Pacific Southwest Region, Fisheries, Wildlife and Rare Plants Staff. 1994.

Newman, G. A. 1970. Cowbird parasitism and nesting success of Lark Sparrows in southern Okalahoma. The Wilson Bulletin 82(3):304-309.

Renwald, J. D. 1977. Effect of fire on Lark Sparrow nesting densities. J. of Range Mgmt 30(4): 283-285.

Rising, J.D. 1996. A guide to the identification and natural history of the sparrows of the United States and Canada. p. 194. Academic Press, San Diego, CA.

Roberson, D. and C. Tenney, Editors. 1993. Atlas of the breeding birds of Monterey County. Monterey Peninsula Audubon Society.

Rosenberg, K. V. 1991. Birds of the Lower Colorado River Valley. University of Arizona Press, Tucson, AZ.

Sauer, J.R., J.E. Hines, I. Thomas, J. Fallow, and G. Gough. 1999. The North American Breeding Bird Survey results and analysis: 1966-1998. Version 98.1. USGS Patuxent Wildlife Research Center, Laurel, MD.

Shuford, W.D. 1993. The Marin County breeding bird atlas: a distribution and natural history of coastal California birds. California Avifauna Series 1, Bushtit Books, Bolinas, California. pp. 314-316.

Small, A. 1994. California birds: Their status and distribution. Ibis Publishing Co. Vista, CA. 342 pp.

Zeiner, D.C., W. Laudenslayer, Jr., K. Mayer, and M. White, eds. 1990. California's wildlife, Vol. 2: Birds. California Department of Fish and Game, Sacramento, 732 pp.

King, A. and G. R. Geupel. 1998. Songbird Response to Restoration Efforts along the Sacramento River: Progress Report from the 1997 Field Season. PRBO report to The Nature Conservancy and Sacramento National Wildlife Refuge.