Grasshopper Sparrow (Ammodramus savannarum)

Account prepared by:  Victor Lyon, United States Fish and Wildlife Service

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Section 1: Species account outline.

SPECIES: Grasshopper Sparrow (Ammodramus savannarum)

SUBSPECIES STATUS: Western Grasshopper Sparrow (A. s. perpallidus) (Coues).


In February of 1999, the California Department of Fish and Game, Natural Heritage Division, Natural Diversity Data Base (NDDB) website ( listed grasshopper sparrows as follows:

As a whole species: "demonstrably secure: commonly found throughout its historic range"; the subspecies A. s. perpallidus as: "restricted range, rare: about 21-100 E.O.’s <viable occurrences>, or 3,000-10,000 individuals, or 10,000-50,000 acres of occupied habitat", the subspecies A. s. perpallidus, in California, as: "endangered, about 6-20 E.O.’s, 1,000-3,000 individuals, 2,000-10,000 acres of occupied habitat".

Grasshopper sparrows are also on the Audubon Society’s Blue List, Partners In Flight’s (PIF) Watch List, and the U. S. Fish and Wildlife Service’s MNBMC (Migratory Non-game Birds of Management Concern) list.

RANGE MAPS (California):

I.  Historical references: Grasshopper sparrows in California favored the coastal zone in the southern part of the state though breeding localities seemed "few and far between" (Pemberton 1917). Records of grasshopper sparrows observed in California prior to 1944 are summarized below in Table 1.

Table 1. Historical records of grasshopper sparrows observed in California.

Lassen County:

Known or probable summer residence in Pete’s Valley (Grinnell, Dixon and Linsdale 1930 in Grinnell and Miller 1944). Trinity County: Known or probable summer residence at Hayfork (Miller and Pitelka in Grinnell and Miller 1944). Tehama County: Known or probable summer residence in Battle Creek Meadows (Grinnell, Dixon and Linsdale 1930 in Grinnell and Miller 1944). Mendocino County: Known or probable summer residence near Ukiah (Dawson 1924 in Grinnell and Miller 1944). Sacramento County: Known or probable summer residence in Sacramento (Ridgway 1874 in Grinnell and Miller 1944). Marin County: Known or probable summer residence at Stinson Beach (Ridgway 1874 in Grinnell and Miller 1944), Nicasio, Tocaloma, Tomales Point, and Black’s Mountain (Grinnell and Wythe 1927 in Grinnell and Miller 1944). Contra Costa County: Known or probable summer residence in Moraga Valley and at Bald Peak (Mus. Vert. Zool. in Grinnell and Miller 1944). Alameda County: Known or probable summer residence in Oakland and Hayward (Grinnell and Wythe 1927 in Grinnell and Miller 1944). San Mateo County: Near Searsville, well after the breeding season on October 25 (Mus. Vert. Zool. in Grinnell and Miller 1944). Santa Cruz County: Known or probable summer residence in Santa Cruz (Dawson 1924 in Grinnell and Miller 1944). Santa Clara County: Known or probable summer residence at Berryessa (Grinnell and Wythe 1927 in Grinnell and Miller 1944). Stanislaus County: Known or probable summer residence in Modesto (Calif. Acad. Sci. in Grinnell and Miller 1944). Merced County: Known or probable summer residence in Chowchilla (Calif. Acad. Sci. in Grinnell and Miller 1944). Mariposa County: Known or probable summer residence in Dudley (east of Coulterville) (Grinnell and Storer 1924 in Grinnell and Miller 1944). Monterey County: Reported present on Point Lobos Reserve (Williams 1937). Fresno County: Known or probable summer residence four miles east of White’s Bridge and in Clovis on February 18 (Tyler 1913 in Grinnell and Miller 1944). Tulare County: Known or probable summer residence in Earlimart (Grinnell 1911 in Grinnell and Miller 1944). Santa Barbara County: Reported breeding on the coast near Santa Barbara (Henshaw 1875 in Willett 1910). Ventura County:
          Reported breeding in the Simi Valley (Appleton 1896 in Willett 1910). Reported "numerous" and breeding in the extreme western end of the Santa Monica Mountains (Pemberton 1917). Los Angeles County: Reported breeding in the San Fernando Valley (Law prior to 1910 in Willett 1910), near Gardena (Willett 1910), Nigger Slough and Gardena (Burnham, Pierce, and White 1917 in Grinnell and Miller 1944). Other records indicative of occurrence in winter and dispersal after breeding: Highland Park, August 10, Los Angeles, October 15 (Swarth 1910 and ibid. 1900 in Grinnell and Miller 1944), and Pasadena (Grinnell 1898 in Grinnell and Miller 1944). Riverside County: Known or probable summer residence in Riverside, Beaumont, and Schain’s Ranch (Grinnell and Swarth 1913, Willett 1933 in Grinnell and Miller 1944). San Bernardino County: Mouth of Lytle Creek Canyon, September 11 (Burnham, Pierce, and White 1917 in Grinnell and Miller 1944). Orange County: Known or probable summer residence at Laguna Beach (Gardner 1915 in Grinnell and Miller 1944). San Diego County: Reported breeding in Escondido, though unusual for the area, following a wet spring (Dixon 1916), San Diego and San Diego County (Huey 1915 in Grinnell and Miller 1944).
II. Current breeding distribution:

Further information is needed regarding the current breeding distribution of grasshopper sparrows in California.

The data gathered from Breeding Bird Surveys conducted 1982-1996 has been compiled by Sauer et al. (1997) to generate, among other things, mean abundance indices of grasshopper sparrows in California by region. In effect, these indices, shown below in Table 2, represent the number of individuals seen, on average, on fifty three-minute counts on early June mornings in each respective region of California.

Table 2. Mean abundance indices of grasshopper sparrows in California by region from Breeding Bird Surveys, 1982-1996 (Sauer et al., 1997)

Mean Abundance
Pitt-Klamath Plateau 0.01
Columbia Plateau 0.1
S. California Grasslands 1.4
Central Valley 0.3
California Foothills 0.2
S. Pacific Rainforests 0.7
Los Angeles Ranges 0.01
I. Average territory size: Male grasshopper sparrows establish territories promptly upon arrival to the breeding grounds and rigidly maintain them until the young hatch. Territorial defense then declines and considerable movement across territory boundaries may occur. It appears that fledglings frequently flutter into adjoining territories and the parent birds follow in answer to the feeding call. A sharp increase in territorial behavior is exhibited during the two or three days prior to re-nesting (Smith 1963). Collier (1994 in Vickery 1996) observed grasshopper sparrow territory sizes of 0.37 ± 0.16 (SD) ha (n=41) in southern California. In other states, territories have been observed to range in size from 1.4 ha (n=6) in Michigan (Kendeigh 1941 in Smith 1968) to 0.19 ± 0.13 (SD) ha (n=20: Piehler 1987 in Vickery 1996) in western Pennsylvania.

II. Time of occurrence and seasonal movements: Data regarding the movements of grasshopper sparrows outside of the breeding season is scarce due to their normally secretive nature (Zeiner et al.1990). Although diurnally active, grasshopper sparrows are easily overlooked as "they seldom fly, preferring to run along the ground between and beneath tufts of grass" (Pemberton 1917). Further, in migration, these sparrows appear to move in small, mixed flocks at night (Vickery 1996).

A. Arrival date on breeding grounds: The first arrivals are the males (Smith 1963) which, depending on latitude, arrive in the Central Valley of California in late February to early March (Collier 1994 in Vickery 1996).

B. Departure dates from breeding grounds: Grasshopper sparrows generally migrate south in August or September (Zeiner et al. 1990).
Spring migration period: The northward migration of grasshopper sparrows through California begins in late February and may last into early May (Collier 1994 and Garrett and Dunn 1981 in Vickery 1996).

C. Fall migration period: Fall migrants on the Farallon Islands have been observed in late July through the first of November, peaking in early October (DeSante and Ainley 1980).

D.  Extent of wintering in California: Grasshopper sparrows are rarely, but regularly, winter residents in California (Zeiner et al. 1990). Christmas Bird Counts (CBCs) in Santa Cruz, San Benito, Monterey, San Luis Obispo, Santa Barbara, Ventura, Kern, Los Angeles, Orange, San Diego, Imperial, Riverside, and San Bernardino counties typically record grasshopper sparrows in very low numbers (averaging one or less bird per CBC route) (Sauer et al. 1995). As they are readily missed in the CBCs because of their very reclusive behavior, Sauer et al. (1995) have expressed that "these limited data are generally insufficient to definitely establish winter population trends."

III. Migration stop-over needs/characteristics:

A. Stop-over period: No information.
B. Habitat use: No information.
C. Routes: Very little information. Known to have visited the Farallon Islands in the late 60’s and early 70’s during fall migration (DeSante and Ainley 1980) (see "Fall migration period" above).
IV.  Nest type: Female grasshopper sparrows build a cup nest in two or three days time. Domed with overhanging grasses and accessed from one side, the rim of the nest is flush with the ground; the slight depression inside fashioned such that the female’s back is nearly flush with the ground while brooding (Dixon 1916, Pemberton 1917, Harrison 1975, Ehrlich 1988, and Vickery 1996). Pemberton (1917) described three identical nests from the Santa Monica Mountains, in southeastern Ventura County, California, as fragile and poorly built of fine grasses with no appreciable lining. Dixon (1917) measured a similar, yet better lined, nest from Escondido, San Diego County, California. The outside dimensions of that nest were 125 mm (5 ½ inches) by 113 mm (5 inches) horizontally, with a depth of 43 mm (2 ¼ inches). The inner cavity measured 69 mm (3 ¼ inches) by 63 mm (3 inches), with a depth of 30 mm (1 ¼ inches).

V.  Foraging strategy: Active search. Vickery (1996) states that exposed bare ground is the critical microhabitat type for effective foraging. Bent (1968 in Zeiner et al. 1990) observed that grasshopper sparrows search for prey on the ground, in low foliage within relatively dense grasslands, and sometimes scratch in the litter.

VI. Displays:

A.  Courtship: The male’s low fluttering flight, done silently or with song, may be answered by a female’s trill. Males may then chase females while singing (Ehrlich 1988).

B.  Territorial: The male alternates between displaying a crouched posture where the head is lowered and the wings are fluttered and singing from the highest perch available (Ehrlich 1988).

C. Distraction: When the nest is approached the female will likely slip off the nest without a trace of commotion and run, or rather sneak away, screened by grass tufts only to appear conspicuously some twenty feet away from the nest and then move further off (Smith 1963). After a short fluttering flight, the female feigns injury, spreading her wings and tail (Ehrlich 1988). Meanwhile, the male may chip and circle the nest at a distance (Dixon 1916). Both may then fly in circles around the nest, raising their crest feathers and flicking their wings and tails, or land and bob up and down on their legs and uttering a sharp chi-ip’s or til-lic’s. (Smith 1963).

VII. Social organization:
A.  Typical breeding densities: Grasshopper sparrows nest in semi-colonial groups of 3-12 pairs (Ehrlich 1988). Smith (1963) recorded breeding densities that ranged from 0.12 to 0.74 males per hectare in Pennsylvania. Collier (1994 in Vickery 1996) observed breeding densities of 0.55 males per hectare in California.

B.  Mating system: Grasshopper sparrows are monogamous through the breeding season (Ehrlich 1988).

C.  Delayed breeding (where are immature birds?): No information.

D.  Post-fledging biology of offspring (where do they go and when?): Little information (see "Average territory size" above).

E. Post-breeding social behavior (do they join in mixed species flocks or simply migrate away?): Grasshopper sparrows do not form winter flocks (Ehrlich 1988).

VII.  Clutch size: 2 to 6, most frequently 4 (n=42) (Smith 1963).

VIII.  Incubating sex: The female alone has a brood patch and incubates eggs (Smith 1963, Ehrlich 1988, Harrison 1975). During incubation, the male defends the pair’s territory (Smith 1963).

VIX.  Incubation period: 11 to 13 days (Smith 1963, Ehrlich 1988, Harrison 1975).

X.  Nestling period: The young fledge at 6 to 9 days after hatching, although still unable to fly (Harrison 1975, Hill 1976, Kaspari and O’Leary 1988).

XI..  Development at hatching: Hatchlings are blind and covered with grayish-brown down (Smith 1968).

XII.  Number of broods: Grasshopper sparrows may produce two broods annually, though protracted favorable weather may allow for a third or, in extreme cases in Florida and Jamaica, a fourth brood (Smith 1963, Ehrlich 1988, Vickery 1996).
Who tends the young: After the young hatch, both parents share the responsibilities of tending the hatchlings and seem more concerned over human intrusion into their territory than before (Smith 1963). Kaspari and O’Leary (1988) observed cooperative breeding by non-parental attendants ("defined as birds bringing food to the nest"). Unrelated juveniles and adults from adjacent territories made 9-50% of the provisioning visits to four of twenty-three nests. Parents facilitated visits from non-parental attendants by moving off the nest yet unrelated birds that did not bring food to the nest were vigorously chased away. Kaspari and O’Leary (1988) suggested that non-parental attendants, rare among the population observed, are likely cases of "misdirected parental care".

XIII.  Diet:

A.  Major food items (by season): The diet, composed of invertebrates (primarily grasshoppers) and seeds, varies by season. Spring diet 60% invertebrates, 40% seeds (n=28); summer diet 61% invertebrates, 39% seeds (n=100); fall diet 29% invertebrates, 71% seeds (n=17), no data for winter (Martin et al. 1951 in Vickery 1996). Major taxa in the diet in mixed prairie (Oklahoma) and tallgrass prairie (S. Dakota) included, respectively: Hymenoptera 0 and 2%, Coleoptera 18 and 10%, Orthoptera 36 and 30%, Hemiptera 9 and 1%, Homoptera 0 and 6%, Lepidoptera larvae 20 and 16%, Araenida 4 and 3%, and seeds 14 and 31% (Wiens 1973b). Grasshoppers, primarily of genera Xiphidium, Scudderia, Hippiscus, and Melanopus, formed 37% of the diet from May through August and 23% the rest of the year (Judd 1901 in Smith 1968). Analysis of the stomach contents of eight grasshopper sparrows taken in California included the following seed types: knotweed (Polygonum sp.), campion (Lychnis sp.), oats, and pigweed (Amaranthus sp.) (Martin et al. 1951 in Vickery 1966).

B.  Drinking: Meets water requirement in part from insects in diet (Zeiner et al. 1990). No further data.

XVI. Wintering grounds needs and distribution: See "Extent of wintering in California" above. Grasshopper sparrows winter south of California to northern South America and in the Greater Antilles (Ehrlich 1988). No further information.


I.  Overview of breeding habitat: Originally restricted to extensive natural clearings and sparsely wooded areas (Smith 1963). Occurs in dry, well-drained native and non-native grasslands, especially those with a variety of grasses and tall forbs for foraging and nesting and scattered shrubs for singing perches. Open grasslands where bunch grasses rather than sod types predominate are selected. "Sod-forming grasses provide a dense mat of vegetation that precludes effective foraging, whereas bunch grasses leave openings or gaps that allow the birds freedom to move about. Also, nest placement is usually associated with bunches of grass" (Whitmore 1981). Occurs mainly on hillsides and mesas in California’s coastal districts (Grinnell and Miller 1944, McCaskie et al. 1979, Garrett and Dunn 1981 in Zeiner et al. 1990). Pemberton (1917) observed grasshopper sparrows on steep hills devoid of vegetation, except for grasses, near canyons harboring live oaks and shrub thickets in Ventura County, California. Also recorded in extensive, alkaline, salt-grass meadow in San Diego County (Dixon 1916). Frequents cultivated grasslands which form bunches (e.g. alfalfa, orchard-grass, and red clover) (Smith 1963). Habitat use is negatively correlated with increasing grass height and litter depth (Smith 1963, Herkert 1994a, Herkert 1994b, Deslisle and Savidge 1997, and Wiens 1969, Skinner et al. 1969, Sample 1989, Herkert 1991b in Herkert 1994b,). Whitmore (1979) documented decreases in population densities in correlation "with increases in vegetation density and a concomitant decrease in bare ground". Abandoned alfalfa fields in Iowa when the vegetation exceeded 30 cm in height (Frawley and Best 1991). Known to maintain approximately equal breeding densities in fields with 0-10% shrub cover, but abandon sites whose shrub cover exceeds 35% (Johnston and Odum 1956). Absence of trees more important than presence of native grasses in southern California (Collier 1994 in Vickery 1996). Appears that vegetation structure, rather than composition, is the more important criteria in breeding habitat selection.

II.  Nest site:

A.  Substrate: Nests are built of grasses, forbs, sedges, and other fine materials, occasionally including hair (Harrison 1975, Ehrlich 1988, Zeiner et al. 1990). These are usually woven into the overhanging grasses. Three identical nests in Ventura County, California were made of fine, dry grasses and lacked an appreciable lining (Pemberton 1917). In San Diego County, Dixon (1916) observed a nest of fine, dead weed stalks (wild oat, salt grass, and some other unidentified species) loosely pressed together. No feathers, fur, or other animal matter were incorporated into the nest.

B.  Height of nest: The nest is built by the female (Harrison 1975) at the base of large tufts of grass (Pemberton 1917). The nest is sunken in a slight depression so that the rim is flush with ground level (Ehrlich 1988) and the female’s back is nearly flush with ground while brooding (Dixon 1916). Dome of nest 5-7 cm high (Simmons 1925 in Smith 1968).

C.  Height of plant: No quantitative information.

D.  Nest concealment: Nest well hidden at the base of an overhanging clump of grasses or forbs (Dixon 1916,
Zeiner et al. 1990).

III. Vegetation surrounding the nest: IV. Landscape factors:
A.  Elevation: Coastal to 1500 m in San Jacinto mountains (Grinnell and Miller 1944, McCaskie et al. 1979, Garrett and Dunn 1981 in Zeiner et al. 1990). Also found in Santa Monica Mountains (Pemberton 1917).

B.  Fragmentation: Habitat fragmentation clearly has a negative effect on grasshopper sparrows. Nest predation and brood parasitism are higher for nests located near (<45 m) a wooded edge than far (>45 m) from a wooded edge (Johnson and Temple 1990).

C.  Patch size: Despite average territory sizes of less than 1 hectare, grasshopper sparrows rarely (<30%) occur on patches even ten times that size (Herkert 1994a). Grasshopper sparrows are significantly more likely to occur in large grasslands. The estimated area requirement (for which the probability of occurrence equals 50% of its maximum) in Illinois was 30 hectares. Using the same measure, Vickery et al. (1994) found the minimum requirement to be 100 hectares. Minimum area requirements from other studies: <20 ha. in Missouri (Samson 1980 in Vickery et al. 1994), 10-30 ha. in Illinois (Herkert 1991 in Vickery et al. 1994). Differences in minimum area requirements may be explained by the effect of relative population level on the selectivity of individuals, as has been shown for many species of birds (O’Connor 1981 in Vickery et al. 1994).

D.  Disturbance (natural or managed): Though habitat-area had a much greater influence on breeding bird community composition, grasshopper sparrows tended to be more numerous on recently burned prairie areas in Illinois (Herkert 1994b). This is consistent with the characterizations of the habitat preferences (low- to medium-height vegetation) of grasshopper sparrows by other studies (Smith 1963, Wiens 1969, Herkert 1994a, Deslisle and Savidge 1997, and Skinner et al. 1984, Sample 1989, Herkert 1991 in Herkert 1994b). However, a severe, natural wildfire that eliminated sagebrush cover in Montana depressed grasshopper sparrow densities for at least three years on shrubsteppe (Bock and Bock 1987 in Vickery 1996). Grasshopper sparrows frequently breed in managed grasslands such as CRP fields and alfalfa fields (Smith 1963). Instances of grasshopper sparrows utilizing fire-induced grassland glades in Michigan (Walkinshaw 1940 in Vickery 1996), capped landfills (A. L. Jones and PDV unpubl. data in Vickery 1996), and restored surface mines (Allaire 1980, Whitmore 1980, Wray et al. 1982 in Vickery 1996) have been recorded.

E.  Adjacent land use: see above.

F.  Other

SPECIAL FACTORS (factors influencing a species occurrence and viability):

A.  Brood parasitism: Hill (1976) observed that while grasshopper sparrows are "very tolerant" hosts of brown-headed cowbirds (60% of cowbird nestlings fledged, n=5), they suffer a "relatively low" (22.2%, n=18) frequency of parasitism in west-central Kansas. In western Minnesota, brood parasitism occurred more frequently at nests of grassland songbirds located near (<45 m) wooded edges than far (>45 m) from wooded edges (Johnson and Temple 1990). The average number of grasshopper sparrows likely to fledge from a parasitized nest is lower than that for a non-parasitized nest (2.0 versus 2.5 in Hill 1976, Johnson and Temple 1986 in Johnson and Temple 1990). Cowbird parasitism in Hill’s (1976) study area occurred from April 16th until July 16th, peaking between April 25th and July 1st. In an about-turn, an instance of egg-dumping by a grasshopper sparrow into a savannah sparrow’s nest was recorded in Wisconsin (Wiens 1971). Wiens (1971) cited Hamilton and Orians’ (1965) suggestion that a female whose nest had been destroyed might be more easily able to dump her un-resorbed eggs into the nest of a bird tolerant of her species rather than a highly territorial conspecific.

B.  Dietary: see "Foraging strategy" and "Diet" above.

C.  Sensitivity to human-induced disturbance: Nests are often destroyed by mowing in cultivated grasslands; despite the loss of cover, birds stay (Smith 1963) and then suffer increased losses from predators (Ehrlich 1988). Grasshopper sparrows display an increased sensitivity to human disturbance after hatching occurs (Smith 1963).
Pesticide use: No information specific to grasshopper sparrows.
Predators: Nest predators cited in the literature include: Raccoons (Procyon lotor), Red Fox (Vulpes vulpes), Northern Black Racers (Coluber constrictor constrictor), Blue Jays (Cyanocitta cristata), and Common Crows (Corvus brachyrhynchos) (Johnson and Temple 1990, Wray et. al 1982). Loggerhead Shrikes (Lanius ludovicianus) commonly take grasshopper sparrows as prey in Oklahoma and Florida (Stewart 1990, D. Wolfe [pers. comm.], and T. F. Dean [pers. comm.] in Vickery 1996). Many other species, especially those not dependent upon sight to find nests, are likely to be nest predators. Gottfried (1978 in Wray et. al 1982) concluded, from his analysis of nest predation in old-field habitats, that snakes were the primary predators and aerial predators were responsible for only minor losses.

D.  Exotic species invasion/encroachment:

E.  Other:

POPULATION TREND: Local abundance fluctuates greatly between years despite available and suitable habitat (Smith 1963, Ehrlich 1988, Deslisle and Savidge 1997). The reason(s) behind these local population fluctuations remains elusive. On a broad scale, continent-wide Breeding Bird Survey (BBS) indices indicate a fairly consistent decline in grasshopper sparrow populations since the mid-1960’s (Sauer 1995). However, BBS indices for western states, including California, indicate a contrary trend in grasshopper sparrow populations over the same time period (Sauer 1995). Winter population trends are more difficult to quantify due to the reclusive nature of grasshopper sparrows following the breeding season. As they are easily missed in the Christmas Bird Counts, that data is thought to be unreliable as a measure of population trends (Sauer 1995). DEMOGRAPHICS:
A.  Age and sex ratios: No information.
B.  Productivity measure(s): No information.
C.  Survivorship: No information.
D.  Dispersal: No information.
MANAGEMENT ISSUES: Whitmore (1981) wrote the following regarding the management of habitat for grasshopper sparrows:
    A.  Burning. Grasslands with encroaching shrubs should be burned during late winter.
    B.  Deferred grazing. Timing of grazing should be delayed until nesting is completed.
    C.  Vegetative reclamation. Reclamation of disturbed sites should be with bunch grasses if grasshopper sparrows are to be encouraged; shrub or tree plantings should be avoided."
"All recommendations are intended to maintain grasslands in an early successional stage with low vegetation density, litter depth and cover, and shrub cover" (Whitmore 1981). Johnson and Temple (1990) stated that "prairie management to maximize nest productivity should provide large, regularly burned prairies with no nearby wooded edges." These conditions corresponded to the fewest losses to predators and brood parasites in their study of five ground-nesting passerines (including grasshopper sparrows). Herkert (1994b) noted that grasshopper sparrows tended to be more common on recently burned prairie areas, though "habitat-area had a much greater influence on bird community composition than did prescribed burning" (see also "Patch Size" above). Large areas of habitat need to be burned on a rotational basis to provide "a mosaic of burned and unburned areas to ensure the availability of suitable habitat for management-sensitive species" (Herkert 1994). Grasshopper sparrows have responded to management efforts in Massachusetts where a population on Westover Air Reserve Base has increased more than 80% in a six-year period (Melvin 1993 in Vickery et al. 1994).

ASSOCIATED SPECIES (a list of other species that would benefit from management of the target species): mourning dove (Zenaida macroura), brown-headed cowbird (Molothrus ater), northern harrier (Circus cyaneus), savannah sparrow (Passerculus sandwichensis), vesper sparrow (Pooecetes gramineus), horned lark (Eremophila alpestris), western meadowlark (Sturnella neglecta), killdeer (Charadrius vociferus), indigo bunting (Passerina cyanea), and others (list, in part, from Wray et al. 1992).

MONITORING METHODS AND RESEARCH NEEDS: Managing an area for grasshopper sparrows should, at a minimum, include obtaining seasonal population indices and monitoring vegetative response and nesting activity. Local nesting activity (which varies according to latitude and almost certainly from season to season) should be monitored to time the implementation of managed grazing activities.

Further research is needed on the following topics: 1) habitat types, stopover areas, and routes used during migration, 2) biology and behavior of fledged, immature grasshopper sparrows, 3) demographics, 4) pesticide use, 5) exotic species invasion/encroachment and brood parasitism in CA, 6) minimum patch size in CA (varied from 10-100 hectares in studies in other states), and 7) habitat structure/composition requirements in CA (grasshopper sparrows abandoned alfalfa fields when the vegetation exceeded 30 cm in height and other sites whose shrub cover exceeded 35% in out-of-state studies).


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