Amphispiza bilineata breeds in the southwest and central regions of North America, extending into the north-central mainland of Mexico. The summer range is much larger than the winter range in the United States. In the winters, it migrates to southern U.S. deserts (Clark,1999; Karl, 2000).

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: BREEDING: eastern Washington, southern Oregon, northeastern California, southwestern Idaho, southwestern Wyoming, southeastern Colorado, northwestern Oklahoma, and north-central Texas south to southern Baja California, the northern Jalisco, Guanajuato, Queretaro, Hidalgo, Tamaulipas, and southern Texas (Godfrey 1966, AOU 1998). NON-BREEDING: from southeastern California, southern Nevada, southeastern Arizona, southern New Mexico, and southern Texas south through breeding range (Godfrey 1966, AOU 1998).

Amphispiza bilineata have dark, conical bills and a black coat, throat and mask. A white supercilium and malar streak are also present. Their crown, back and wings are grey and their bellies are white. The round tail is long and black with a few white patches on outer feathers (INRIN).

Juvenile black-throated sparrows are much browner and have a faint adult face pattern. The young have facial stripes but are also finely streaked on throat, instead of a completely black throat (Robbins, 1966).

Average mass: 12 g.

Range length: 12.1 to 13.4 cm.

Average length: 11.4 cm.

Average mass: 11.6 g.

Average basal metabolic rate: 0.1988 W.

Length: 14 cm

Weight: 14 grams

• Terrestrial

The black-throated sparrow prefers a sparse, isolated desert environment. Hot, dry weather in the desert uplands, creosote bush and scrub environments are the most frequent habitats. These sparrows prefer terrain that is either steeply sloped or very flat. Besides desert uplands, they also favor alluvial fans and hill slopes, usually with much exposed rock and gravel pavement (INRIN; Karl, 2000).

Plants that are closely associated with this species include creosote bush and cholla cactus, catclaw, small mesquite, artemisia, rabbit-brush, purshia, dwarf juniper, yucca, agave, and sagebrush (Robbins, 1966).

Habitat Regions: terrestrial

Terrestrial Biomes: desert or dune

Comments: BREEDING: Frequents the arid, hot deserts of the West. Not closely associated with particular plant species or communities, but favors sparsely vegetated desert scrub, including thorn brush, cacti, chaparral, mesquite and juniper. It is most often found on desert uplands, alluvial fans, and hillsides where thorny xeric brush dominates, and sometimes also in dry shrubby washes, but avoids desert valley floors. Occurs from below sea level (Death Valley) to over 2,200 meters, but below 1,500 in northern parts of range (Bent 1968, AOU 1983, Howell and Webb 1995, Rising 1996). It uses all seral stages in desert habitats as long as vegetative cover is below 25 percent, and uses shrubs and cacti for foraging, song perches, lookouts, shelter and nesting (USDA Forest Service 1994). May take advantage of mammal burrows to escape desert heat (Austin and Smith 1974).

Found in a variety of desert scrub and chaparral habitats, including ocotillo (Fouquieria splendens), cholla (Opuntia spp.), mesquite (Prosopis spp.), catclaw (Acacia greggii), blackbrush (Coleogyne ramosissima), saltbush (Atriplex spp.), greasewood (Sarcobatus vermiculatus), canotia (Canotia holacantha), and creosote bush (Larrea tridentata) interspersed with taller plants such as Joshua trees (Yucca brevifolia). In other areas found in sagebrush (Artemisia sp.), antelope brush (Purshia tridentata), or rabbitbrush (Chrysothamnus spp.) interspersed with pinyon-juniper (Bent 1968, USDA Forest Service 1994, Rising 1996). In Idaho, recorded in open shrublands where dominant shrubs were more than 50 cm tall, in big sage (Artemisia tridentata), spiny hopsage (ATRIPLEX SPINOSA), and horsebrush (Tetradymia spp.) along with other shrubs (Marks et al. 1980). On Tiburon Island, Baja California, found breeding in littoral scrub that included salt scrub and mangroves, as well as in xeric thorn scrub (Wauer 1992).

Nests are well-concealed and placed at the base of a bush or cactus, on or near the ground (but usually about 15-45 centimeters above ground) hidden in a grass tuft, fork of dense shrub, or joints of a cactus (USDA Forest Service 1994, Baicich and Harrison 1997). In Idaho, a sample of nine nests were all found 25-45 cm above the ground in big sagebrush shrubs, but sparrows were never observed in the dense stands of big sagebrush typically inhabited by sage sparrows (Amphispiza belli) and Brewer's sparrows (Spizella breweri). In Arizona, nests observed in bases of creosote bush and in cholla (Tomoff 1974). In south-central New Mexico, used 25 different plant species for nesting; placed nests within 49 cm of ground; nested significantly more frequently on uplands with abundant small shrubs than in arroyos, and produced larger clutches and fledged more young in upland territories (Kozma and Mathews 1997). In other studies, have been found nesting in shrubby washes and arroyos (Raitt and Maze 1968, Medin 1986). Preference for upland or wash may be tied to local availability of dense or spiny shrubs that afford concealment and protection, or perhaps avoidance of areas prone to flash floods.

NONBREEDING: In addition to xeric shrub habitats, may be found in riparian areas, grasslands and weedy fields away from desert region (AOU 1983, Rising 1996). Associated with shrubs in the grasslands of the Mexican Plateau, Chihuahua, Mexico (Colorado Bird Observatory 1997). Foraging flocks may follow local topography, particularly washes (Eichinger and Moriarty 1985).

FORAGING: Will forage in mesquite, catclaw, desert willow (Salix sp.) for insects (Bent 1968).

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).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

Migrant in northern parts of range. In northern Arizona, departs mid-August, returns late March; in southern Arizona, arrives in early March (Phillips et al. 1964).

Black-throated sparrows are omnivorous, eating seeds during winter months and insects during breeding season. They eat many flying insects, but also consume grasses and herbs. Gravel is sometimes ingested to aid in digestion. This bird can usually be observed running around on the ground in search of insects. The diet of insects allows these birds to obtain moisture from their food and not rely on free water throughout breeding season. If spring water is present they will take advantage of it. The young are fed insects, particularly grasshopper abdomens (Karl,1999; Clark, 2000; DeLacy, 2001).

Common foods eaten include: angiosperms (flowering plants), Poaceae (grasses), seeds from deciduous shrubs, arthropods, grasshoppers and crickets, and  cockroaches.

Animal Foods: insects

Plant Foods: leaves; seeds, grains, and nuts

Primary Diet: omnivore

Comments: Feeds on seeds, insects, spiders, and green grass shoots. In winter, feeds primarily on seeds; in breeding season on insects. Forages on the ground; ingests gravel while ground feeding. Will also glean insects from shrubs and herbs and will hawk aerial insects. Young are fed insects, especially grasshoppers. During some seasons this species can obtain daily water requirement from insects and green vegetation; in dry season, when seeds are main food source, will drink regularly at water holes (Bent 1968).

In Arizona and Texas, there have been reports of A. bilineata serving as a host to cowbirds (Terres, 1980).

An anti-predation adaption the black-throated sparrow has developed is to "freeze" when a predator is near their nest. This most likely occurs because predators are more likely to search an area from where a bird has just been flushed (DeLacy, 2001; INRIN).

Known Predators:

• snakes (Serpentes)
• coyotes (Canis latrans)
• Canadian lynx (Lynx canadensis)

Relative abundances recorded on BBS routes are high, ranging from and average 11.76 to 23.42 birds per 25-mile survey route. Density of 7 per 40 hectares has been reported for desert scrub creosote-burrobush habitat in California (Kubik and Remsen 1977); in another study, 3.9 per 40 hectares (Bureau of Land Management, no date). In southern Utah, breeding densities ranged from 4.3 to 9.6 pairs per 40 hectares (Medin 1986). In a creosote bush community in Nevada, occurred in densities of 43-61 pairs per 100 hectares (Hill 1980). In Baja California, average density of individuals was significantly higher on island study sites (16 individuals per 10 hectares) than on mainland sites (7.0 per 10 hectares; George 1987a). In New Mexico creosote bush scrub habitat, territory sizes were estimated at 120-150 meters in diameter (Heckenlively 1967).

Chases are common among males when territories are being established (Rising 1996). Visibility in habitat can be limited, and singing both elicits defense behavior and is apparently the most frequent response for territorial defense (Heckenlively 1967).

During nonbreeding season, found in small foraging flocks and often in mixed-species flocks that may include sage sparrows (Amphispiza belli), Brewer's sparrows (Spizella breweri), white-crowned sparrows (Zonotrichia leucophrys), vesper sparrows (Pooecetes gramineus), cactus wrens (Campylorhynchus brunneicapillus) or verdins (Auriparus flaviceps; Ehrlich et al. 1988, Rising 1996).

In a study conducted between early March and late May in southern Arizona, birds foraged on ground more than 90 percent of the time (Parker 1986). Seed foraging is apparently facilitated by the presence of rodents and ants, possibly through the creation of runways and bare areas which the sparrows use for visual foraging. Sparrow abundance declined over the long-term with the removal of rodents and ants (Thompson et al. 1991).

Average lifespan

Status: wild: 72 months.

The black-throated sparrow breeds in most desert states of the United States and Mexico. In California, song and pair formation begin in February. Depending on the timing of the rains, nesting behavior begins in March and continues through mid-August. The nest is built from April to June and is normally well concealed in shrubs and bushes. In Idaho, all of the nests were within 25 cm of the ground. The nest is cup-shaped and loosely built of grasses and stems. It is lined with plant fibers, rabbit fur, cow hair, wool, and feathers. From April to August there are two broods, with usually 3 to 4 eggs laid in each. The eggs are either white or pale blue and average 17.3 to 13.8 mm in diameter. Incubation period and age when young fledge are unreported (DeLacy, 2001; INRIN; Kaufman, 1996).

Breeding season: spring/summer

Range eggs per season: 3 to 4.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)

Average eggs per season: 3.

Both parents play an active role in feeding the young. The male also protects the nest by using his song to warn off other conspecifics (Kaufman, 1996).

Parental Investment: altricial ; male parental care ; female parental care

Clutch size two to four, usually three to four. Duration of incubation and nestling periods are unknown. Nestlings are altricial and downy. Nesting occurs from February through mid-August, depending on region; most records between April and June; time of breeding can vary greatly from year to year depending on rainfall and food abundance (George 1987b, Ehrlich et al. 1988, Rising 1996). Will raise two broods (Ehrlich et al. 1988). In a creosote bush community in Nevada, this sparrow was found to be one of only two bird species that bred during dry years (Hill 1980). One record of egg-dumping of a Sage Sparrow (Amphispiza belli) egg in a black-throated sparrow nest, in an area where territories overlapped (Gustafson 1975).

During times of hot months with limited water, can apparently suppress normal adrenocortical response to heat stress, which may allow breeding to continue despite extreme temperatures; the response is then reactivated in winter months (Wingfield et al. 1992).

This sparrow is a non-game bird protected by the Migratory Bird Treaty Act. In desert areas where development is increasing, its populations have declined. Unlike some desert birds, the black-throated sparrow does not adapt well to life in the suburbs. In proper habitat, however, its population is steady (INRIN; Kaufman, 1996).

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Comments: Causes of population decline and threats to the species are largely unknown. In some areas, habitat may be lost to spreading urban development or wildfires. PREDATORS AND COMPETITORS: Vulnerable to nest predators. Predators include snakes, mammals and birds (Bent 1968, George 1987a). In a study in south-central New Mexico, nest predation was greatest factor in nest failure; predation rates did not differ between upland and arroyo territories; and the authors suspected that snakes were the primary predators (Kozma and Mathews 1997). In Baja California, George (1987a) found lower predation rates and higher nesting densities on islands than on the mainland Peninsula. Total density and number of species of avian nest predators was lower on the islands than on the mainland. May compete for nest sites with sage sparrow (Amphispiza belli; Bent 1968). BROOD PARASITISM: Classed as an uncommon cowbird host (Ehrlich et al. 1988). Several instances of Brown-headed Cowbird (Molothrus ater) parasitism in Texas and Arizona were noted by Bent (1968). In a New Mexico study, 10% of 141 nests were parasitized (Kozma and Mathews 1997).

Restoration Potential: Although is relatively widespread in the desert southwest and abundant in appropriate habitats, it occurs in relatively fragile environments which may require considerable time to restore once degraded. A better understanding is needed of the ecology, threats, causes of population declines, and the management and restoration potential of its preferred habitats to sustain populations over the long term. See Roundy et al. (1995) for information on arid shrubland restoration.

Preserve Selection and Design Considerations: Landscape relationships, response to habitat fragmentation, area sensitivity, and importance of habitat corridors are all unknown. Establishes fairly large territories in specific desert habitats with sparse cover, so it may prove vulnerable to habitat fragmentation.

Management Requirements: Requires desert scrub habitats with sparse shrubs (below 25 percent vegetative cover) and water sources during dry seasons (USDA Forest Service 1994). There is almost no quantitative information on the impacts of human activities. The desert habitats preferred by the sparrow tend to be fragile and vulnerable to degradation and can take a long time to recover from activities such as recreation, off-road vehicle use, heavy grazing, and mining, or from land conversions such as urban development and agriculture. Nest on or very close to the ground and may be sensitive to ground disturbances such as human traffic, off-road vehicles, or trampling by livestock (USDA Forest Service 1994, Paige and Ritter 1998).

GRAZING: Certain grazing regimes may promote the desert shrub habitats. Showed a positive response to moderate grazing in a semidesert grassland in southern Arizona (Bock et al. 1984). In a shadscale habitat in southwestern Utah, Medin (1986) found higher mean densities in experimental plots heavily grazed in early and mid-winter (7.9 pairs per 40 hectares and 9.6 pairs per 40 hectares), than in an late-winter grazed plot or an ungrazed plot (4.3 pairs per 40 hectares and 4.6 pairs per 40 hectares). However, within the study plots the birds were restricted to dry washes with tall shrubs, and the early and mid-winter grazed plots contained considerably more shrub cover than the late-winter grazed plot. Much further study is needed to better understand the effects of grazing on habitat, abundance, and productivity.

Management Research Needs: Information needed on the landscape relationships and response to habitat degradation, fragmentation, and alteration. Need studies of the effects of grazing regimes, recreation activities, off-road vehicles, wildfire, and other impacts on habitat, particularly in relation to productivity and survival. Also need further study of brood parasitism rates and behavioral response to parasitism.

Biological Research Needs: More information is needed on the species habitat requisites and preferences, particularly in migration and winter; breeding site fidelity; flocking behavior; diet and feeding behavior; interrelationships with other species, including predators, competitors, and possible facilitators (such as rodents and ants); predation and brood parasitism rates in relation to habitat.

There is no documented economic importance these birds have for humans. They add to the biodiversity of the desert and bring a beautiful chorus to the world.

Stewardship Overview: Abundant in its favored desert habitats, but very little is known about the life history and management needs. Populations have apparently undergone a widespread decline over the last thirty years, although increases are also apparent in some areas of its range. Causes of declines and threats are unknown. Activities that degrade, fragment, or destroy the preferred fragile arid scrub uplands would be detrimental.

Species Impact: Likely plays an ecological role as a seed disperser, but this is unstudied.