San Diego Management & Monitoring Program


Southern California rufous-crowned sparrow
Aimophila ruficeps canescens

Vertebrata

Vertebrata
Kingdom Phylum Subphylum Class Order Suborder Family

Current distribution rangewide

Species range is discontinuous, inlcuding many small and isolated populations throughout the western U.S. and Mexico [1]. A resident of southwest California on the slopes of the Transverse and Coastal ranges from Los Angeles County south to Baja California Norte. Can also be found on San Martin Island [1;2, cited in 7]. Typically found between 2000 and 6000 feet in elevation [3]. Descend to lower elevations outside their normal range during severe winters [1].


Known Populations in San Diego County

Known to occur along the coast within Camp Pendleton, Torrey Pines State Reserve, and Point Loma, down to lower elevational areas in eastern Camp Pendleton, Fallbrook Naval Weapons Station, Mission Trails Regional Park, Miramar east to San Vicente Reservoir and Lake Jennings, and from Sweetwater Reservoir east to Rancho Jamul [4].


List status

None.


Habitat affinities

Widespread over the coastal lowland and foothills of San Diego County in sage scrub, broken or burned chaparral, and grassland with scattered shrubs [4]. Prefers open shrubby habitat on rocky, xeric slopes [5;6; both cited from 7;8]. Average habitat is fairly steep south-facing slopes with about 50% cover of low shrubs [4]. In California, breeds in sparsely vegetated scrubland on hillsides and canyons. Can also be found breeding in coastal bluff scrub, low-growing serpentine chaparral, and along the edges of tall chaparral habitats [1;6, cited from 7]. Thrive in areas that have recently been burned, and will stay in such open, disturbed habitats for years until the chaparral matures [1;4;6, cited from 7].


Taxonomy and genetics

Currently 17 recognized subspecies, 5 that occur in the United States and 12 that occur in Mexico [1]. Of the 5 subspecies that occur in the U.S., 2 inhabit the desert southwest (A. r. scottii and A. r. eremoeca) and 4 are found in California (A. r. canescens, A. r. obscura, A. r. ruficeps, and A. r. scottii) [1;2, cited in 7]. Previously known as the ashy Rufous-Crowned Sparrow. A. r. canescens occurs in San Diego County and is restricted to the San Diegan District of the California Floristic Province [4].


Seasonal activity

Not migratory [9]. Diurnal [9;10].


Life history/ reproduction

Monogamous [7;9]. Breeds from mid-March to mid-June with a peak in May [9]. Pair bonds appear to be maintained throughout the breeding season and possibly year-round [6, cited in 7] with an apparent majority of birds paired for mulitple breeding seasons [11]. Males defends territories year-round [7]. Nests primarily on ground, rarely in low shrubs [4]. Clutch usually 3-4 eggs, occasionally 2-5 (1;10]. Only the female incubates [6, cited in 7;10; 12, cited in 9]. Incubation appears to last 11-13 days [7]. Chicks are altricial [1;7;12, cited in 9]. Female begins brooding immediately after hatching occurs and is the only parent to brood [7]. No information on adult survivorship [1].


Diet and foraging

Primarily feeds on small grass and forb seeds, fresh grass stems, and tender plant shoots during the fall and winter [1;10;13, cited in 9]. Occasionally consumes insects such as ants, grasshoppers, ground beetles, and scale insects. Insects and spiders become more common in diet during the breeding season [1;13, cited in 9]. Forages on or very near the ground while walking or hopping under shrubs or within dense grass or herbaceous cover [8]. Rarely forages in open areas [2, cited in 7]. Glean insects from low shrubs, grasses, and low herbaceous vegetation. Actively forage throughout the day, obtaining most of their food by pecking or rarely scratching through leaf litter [14, cited in 1]. Forages in pairs during the breeding season, in family-sized flocks in the late summer and early fall, and can occasionally be found foraging in loose-knit mixed species flocks during the winter [1].


Dispersal

Year-round resident [1;4;7]. Exhibit high nest-site fidelity, returning to the same location to nest in subsequent years [11]. Juveniles probably disperse only a few miles from the place where they hatched and adults remain in their established territories for life [4].


Threats

Threatened by habitat loss, fragmentation, and degradation due to agricultural conversion, urban development, and fire suppression [5, cited in 7].


Southern California rufous-crowned sparrow sources