range map

action plan summary

references

SUBSPECIES STATUS:

No recognized subspecies (Baltosser and Scott 1996).

MANAGEMENT STATUS:

No special status.

DISTRIBUTION:

HISTORICAL DISTRIBUTION:

Grinnell and Miller (1944) describe the distribution as San Diegan district northwest through Ventura County, and Colorado and Mohave deserts, with vagrants noted as far north as Oakland. Nesting reported as far north as Owens Valley (Inyo County) and Salinas Valley (Monterey County). Reported to be common to abundant within its range.

CURRENT BREEDING DISTRIBUTION:

Zeiner et al. (1990) report that Costa's Hummingbirds are common and widespread in southern California, and breed locally along the western edge of San Joaquin Valley, along the eastern edge of the Sierra Nevada north to Inyo County, and in Monterey County. In the winter, they are restricted to the southern coastal areas and deserts. Unitt (1984) describes Costa's Hummingbird as ranging throughout San Diego County. The species is a fairly common to common breeding resident along the coastal slopes and in the deserts and occurs as a summer visitor up to the highest elevations in the county. Massey (1998) states that Costa's Hummingbirds occur in small numbers year-round in the Anza- Borrego Desert, although most are migrants that arrive in late winter and nest through early spring. Lehman (1994) describes the status of Costa's Hummingbird in Santa Barbara County as "Fairly common summer resident of drier sections of all districts. Very uncommon transient away from breeding areas. Rare to very rare in winter, primarily on the coast."

Between 1992 and 1997, the Cleveland National Forest conducted point counts at a total of 200 points for chaparral bird species. This study resulted in the location of about 60 Costa's Hummingbirds each year, in the Pine Valley area of San Diego County (USDA Forest Service 1997).

Breeding Bird Atlases:

Orange County BBA - Common as a summer resident of parks and natural areas. Rare as a winter resident in parks and residential areas (Gallagher 1997).

Los Angeles BBA - Costa's Hummingbird is most common in the foothills of Los Angeles County (Garrett 1994).

Monterey BBA - Between 1988 and 1992, Costa's Hummingbirds were detected as rare and local summer residents of dry coastal sage scrub and xeric chaparral in Monterey County, with an estimated population of about 100 adults (Robersen and Tenney 1993).

WINTERING DISTRIBUTION:

Winters in southern California, southwestern Arizona, and in Mexico, on Baja Peninsula and on mainland Mexico near the Sea of Cortez in Sonoran desert scrub; in coastal California, winters in residential areas and parks with exotic plantings (Baltosser and Scott 1996).

ECOLOGY:

AVERAGE TERRITORY SIZE:

Few published studies. Individuals apparently defend territories when nectar resources are limited, but do not defend territories when nectar is abundant or plants are dispersed. Outside of breeding season, adults and juveniles of both sexes defend feeding territories (Baltosser and Scott 1996).

TIME OF OCCURRENCE AND SEASONAL MOVEMENTS:

Arrival date on breeding grounds:

Baltosser and Scott (1996) state that Costa's Hummingbirds arrive in California desert regions between February (in the south) and April (in the north), and remain through June or later. Along the California coast, Costa's Hummingbirds are present between March and September. In San Diego County, some birds are present year-round. Breeding occurs from early spring through summer, with egg dates for coastal regions ranging from April 17 to June 13, and egg dates for desert areas ranging from March 30 to April 11 (Unitt 1984). In Orange County, birds are common between March and August, with nest-building detected from April 23 through June 6 (Gallagher 1997). In Santa Barbara County, spring migrants appear in late March to early April. Birds leave nesting areas in late June or July, and are rare after August. The earliest record reported for the county is February 25 and the latest record is October 15 (Lehman 1994).

It has been suggested that migratory populations of Costa's Hummingbird first raise one brood in the desert and then move west to the coastal ranges to raise a second brood (Stiles 1973). In Arizona, the earliest nesting date was January 29 (nest with eggs) while the latest evidence of breeding was nest building on June 3 (ABBA unpubl. data).

Departure date from breeding grounds:

See above.

Spring migration period:

February - April

Fall migration period:

July-October

Extent of wintering in CA:

Although earlier authors reported that Costa's Hummingbirds were present only in spring and summer, more recently this species has occurred in San Diego County as a year-round resident, nectaring on cultivated ornamental plant species that flower year-round (Unitt 1984). Massey (1997) found Costa's Hummingbirds were present throughout the Anza-Borrego desert in all months, although few were seen in September and October. Lehman (1994) reports that an average of 1 to 3 Costa's Hummingbirds are detected in Santa Barbara County each winter, mostly in the coastal areas.

MIGRATION STOPOVER NEEDS/CHARACTERISTICS:

Stop-over period:

No information.

Habitat use:

In migration, Costa's Hummingbirds use the same types of habitat that they breed and winter in (Baltosser and Scott 1996).

Routes:

No information.

FOOD HABITS:

FORAGING STRATEGY:

Hovers and feeds on nectar from flowers, flycatches insects, probably gleans small spiders and insects from vegetation (Baltosser and Scott 1996).

DIET:

Feeds on nectar and small insects year-round; flycatches insects or may glean small insects from plants (Baltosser and Scott 1996).

DRINKING:

Usually can obtain sufficient water from food. Will visit water sources and drink when free water is available (Baltosser and Scott 1996).

BREEDING HABITAT:

NEST SUBSTRATE:

May use a variety of shrubs and trees. In deserts, cacti, paloverde, jojoba, and smoke trees are commonly used. Dawson (1923) found that Costa's Hummingbirds frequently nested in riparian areas of Santa Barbara County, where oak, alder, sycamore or bay trees were present. In San Diego County, shrubs and trees such as buckwheat and coast live oak are common substrates (KW pers.obs.). The nest is usually placed near the ends of twigs or in an area that affords the bird a clear view (Baicich and Harrison 1997).

HEIGHT OF NEST:

Nest height is typically 4-5 feet, sometimes 1-9 feet (Harrison 1979).

NEST CONCEALMENT:

Nest generally placed in an exposed location (Baicich and Harrison 1997).

VEGETATION SURROUNDING NEST:

CANOPY COVER:

Varies, nest is usually near water where shrubs and trees are present (Baicich and Harrison 1997). In Sonoran desert scrub, foliar cover over nest is approximately 30% (Baltosser and Scott 1996).

DOMINANT PLANT SPECIES IN CANOPY:

In California deserts, may occupy areas dominated by smoke trees, catclaw acacia, cholla, and desert willow (Baltosser and Scott 1996). In coastal California, may use various chaparral habitats and riparian areas. Dominant species may include chamise, laurel sumac, buckwheat, California lilac, coffeeberry (Stiles 1973).
In Arizona, the Breeding Bird Atlas and Partners in Flight programs (Latta et al. 1999) found that breeding habitat for the Costa's Hummingbird is strictly within the Sonoran desert scrub habitat, rarely exceeding 1000 m in elevation, primarily in southwestern and southcentral Arizona.

DISTANCE TO WATER:

Nest is usually near water where shrubs and trees are present (Baicich and Harrison 1997).

NEST TYPE:

Cup nest made of plant fibers held together with spider silk. Often lined with small dark feathers. Exterior of nest has distinctive grayish appearance. Outside nest diameter about 1 ½ " with a depth of about 1 ½ ". Female continues to build up the nest during incubation (Harrison 1979).

BREEDING BIOLOGY:

TYPICAL BREEDING DENSITIES:

Varies with resource availability. Females may nest in close proximity to each other with nests within 35 meters of each other. In the desert, nests are usually 100 meters or more apart (Baltosser and Scott 1996).

DISPLAYS:

For territorial defense, will rapidly fly at and chase intruders. During breeding season, males perform aerial loops accompanied by whistles to impress females. Males may also whistle while perched (Baltosser and Scott 1996).

MATING SYSTEM:

Males are promiscuous.

CLUTCH SIZE:

Two long-oval white eggs (Harrison 1979).

INCUBATING SEX:

Female (Baicich and Harrison 1997).

INCUBATION PERIOD:

15-18 days (Baicich and Harrison 1997).

DEVELOPMENT AT HATCHING:

Altricial.

NESTLING PERIOD:

20-23 days (Baicich and Harrison 1997).

PARENTAL CARE:

The female tends the young. (Baicich and Harrison 1997).

POST BREEDING SOCIAL BEHAVIOR:

Fledglings remain near nest and are fed by female for at least one week. Males may perform rudimentary displays within 3-4 weeks of fledging (Baltosser and Scott 1996).

NUMBER OF BROODS:

Usually one, rarely two (Baltosser and Scott 1996).

BROOD PARASITISM:

Not reported for this species (Baltosser and Scott 1996).

LANDSCAPE FACTORS:

ELEVATION:

In California, breeds from near sea level to about 3000' (Baltosser and Scott 1996).

FRAGMENTATION:

Appears to retreat from developed areas, where it may be outcompeted by Anna's Hummingbird or other hummingbird species (Baltosser and Scott 1996).

PREDATORS:

Egg and nest predation are the major source of mortality at most sites. Important predators are snakes, small mammals, jays, orioles, and lizards. Adults may be preyed on by Greater Roadrunners and thrashers (Baltosser and Scott 1996).

EXOTIC SPEICES INVASION/ENCROACHMENT:

The increasing abundance of non-native grasses in western deserts is making these habitats more fire-prone. Most desert plant species are not adapted to fire, and habitat quality usually decreases after fire (Baltosser and Scott 1996).

COMPETITION WITH OTHER HUMMINGBIRDS:

Costa's Hummingbirds are usually subordinate to other species of hummingbirds, and may be excluded from areas by other species (Baltosser and Scott 1996).

DEMOGRAPHY AND POPULATION TRENDS:

AGE AND SEX RATIOS:

No information.

PRODUCTIVITY MEASURE(S):

Reported nest success rates range from 9% to 41%, with nest failures due to predation, abandonment, weather or accidental destruction (Baltosser and Scott 1996).

SURVIVORSHIP:

No information.

DISPERSAL:

No information.

POPULATION TREND: http://www.mbr-pwrc.usgs.gov/bbs/bbs.html

BBS Data: Range-wide, BBS trend data between 1980-2000 showed an increase of 2.9% per year. For California, it showed an increase of 0.6% per year. Due to small sample sizes, low detection rates, or high variability, these data should be used with caution (Sauer, J. R., J. E. Hines, and J. Fallon. 2001).

MANAGEMENT ISSUES:

Agricultural and urban development is reducing the amount of native habitat available to Costa's Hummingbirds.

Migration routes are not well understood.

Fire return intervals may affect habitat suitability. In chaparral, the first few years after fire appear to favor Costa's Hummingbirds due to the abundance of wildflowers. In desert habitat, fires may result in loss of woody vegetation, making habitat unsuitable for Costa's Hummingbirds.

In urban areas, Costa's Hummingbirds do not appear to compete well with other species of hummingbirds.

ASSOCIATED SPECIES:

Desert populations: Ladder-backed Woodpecker, Le Conte's Thrasher, Ash-throated Flycatcher, Verdin, Black-tailed Gnatcatcher, Cactus Wren, White-winged Dove, Phainopepla, and Scott's Oriole.

Coastal and foothill populations: Black-chinned Hummingbird, Lesser Goldfinch, Ash-throated Flycatcher, Spotted Towhee, Western Scrub Jay, Black-chinned Sparrow, Bushtit, Bewick's Wren, Sage Sparrow, Lawrence's Goldfinch.

MONITORING METHODS AND RESEARCH NEEDS:

1. Use GIS models to compare the distribution of Costa's Hummingbirds to landscape features such as fire history, vegetation type, etc. Use this information to identify key habitat areas for conservation.

2. Investigate the possibility of banding or genetic studies to track migration routes.

3. Study the effects of fire on Costa's Hummingbird habitat in a range of habitat types.

4. Investigate the limiting factors for Costa's Hummingbirds in urban areas.

ACTION PLAN SUMMARY

SPECIES: Costa's Hummingbird (Calypte costae)

STATUS: No special status.

No recognized subspecies.

Most populations appear stable or are increasing slightly at this time.

HABITAT NEEDS:

Breeding territory sizes vary widely depending on habitat type and resource availability.

The breeding range includes southern California, southern Utah and Nevada, southwestern Arizona , southwestern New Mexico, and Baja California and mainland Mexico. The breeding range is typically occupied beginning in February through May, and ending in July- September.

Costa's Hummingbirds are mostly migratory, overwintering in Mexico or in the deserts of the southwestern US (Texas, Arizona and California).

Habitat associations vary throughout the breeding range of the Costa's Hummingbird. In the Peninsular Ranges of southern California, found in coastal sage scrub or in chaparral dominated by chamise and cup-leaf ceanothus. In the desert areas of California, found in desert scrub and desert wash habitat dominated by smoke trees, desert willow, and cactus.

Winter range in California, Arizona and Mexico consists of Sonoran desert scrub; a few individuals overwinter in coastal areas in parks or gardens.

Feeds on nectar and insects year-round.

Open-cup nests are built in shrubs or trees at heights of 1 to 3 feet above the ground. Average clutch size is 2 eggs. One or two broods are raised.

CONCERNS:

Agricultural and urban development is reducing the amount of native habitat available to Costa's Hummingbirds.

Migration routes are not well understood.

Fire return intervals may affect habitat suitability. In chaparral, the first few years after fire appear to favor Costa's Hummingbirds due to the abundance of wildflowers. In desert habitat, fires may result in loss of woody vegetation, making habitat unsuitable for Costa's Hummingbirds.

In urban areas, Costa's Hummingbirds do not appear to compete well with other species of hummingbirds.

OBJECTIVES:

Ensure that sufficient habitat is protected.

Increase the understanding of migration routes.

Determine the effect of fire on habitat.

Determine the reasons for the rarity of Costa's hummingbirds in urban environments.

ACTION:

1. Use GIS models to compare the distribution of Costa's Hummingbirds to landscape features such as fire history, vegetation type, etc. Use this information to identify key habitat areas for conservation.

2. Investigate the possibility of mark/recapture studies to track migration routes.

3. Study the effects of fire on Costa's Hummingbirds in a range of habitat types.

4. Investigate the limiting factors for Costa's Hummingbirds in urban areas.

REFERENCES:

Baltosser, W.H. and P.E. Scott. 1996. Costa's Hummingbird (Calypte costae). In The Birds of North America, vol. # 251 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA.

Baicich, P.J. and C. J. O. Harrison. 1997. A guide to the nests, eggs, and nestlings of North American birds. 2nd ed. Academic Press, London,UK. 347 pp.

Dawson, W.L. 1923. The birds of California. Volume 2. South Moulton Co., San Diego.Gallagher, S.R. ed. and primary author. 1997. Atlas of Breeding Birds of Orange County. Sea and Sage Press, Irvine, CA.

Garrett, K. 1994. Bird species accounts, in Atlas Handbook for the Los Angeles County Breeding Bird Atlas. Natural History Museum of Los Angeles, Los Angeles, CA.

Garrett, K. and J. Dunn. 1981. Birds of southern California: status and distribution. Los Angeles Audubon Society, 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. Cooper Ornithological Club, Berkeley, CA.

Harrison, H. 1979. Western Bird Nests, Peterson Field Guides. Houghton Miflin Co, NY, NY. 279. pp.

Latta, M.J., C.J. Beardmore, and T.E. Corman. 1999. Arizona Partners in Flight Bird Conservation Plan. Version 1.0. Nongame and Endangered Wildlife Program
Technical Report 142. Arizona Game and Fish Department, Phoenix, AZ.

Lehman, P.E. 1994. The Birds of Santa Barbara County, California. Vertebrate Museum, University of California, Santa Barbara

Massey, B. 1998. Guide to Birds of the Anza- Borrego Desert. Anza Borrego Desert Natural History Association, Borrego Springs, CA. 292 pp.

Robersen , D. and C. Tenney, eds. 1993. Atlas of the Breeding Birds of Monterey County. Monterey Peninsula Audubon Society, Monterey, CA. 438 pp.

Sauer, J. R., J. E. Hines, and J. Fallon. 2001. The North American Breeding Bird Survey, Results and Analysis 1966 - 2000. Version 2001.2, USGS Patuxent Wildlife Research Center, Laurel, MD

Stiles, F.G. 1973. Food supply and the annual cycle of the Anna's Hummingbird. Univ. Calif. Publ. In Zool. 97:1-109.

Unitt, P. 2002. Personal communication. Curator, Dept. Birds and Mammals, San Diego Natural History Museum, San Diego, CA.

Unitt, P. 1984. Birds of San Diego County. San Diego Natural History Society.

USDA Forest Service. 1997. Chaparral bird study. Cleveland National Forest files, San Diego, CA.

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.