Abert's towhee (Pipilo aberti)
Written by: D. Dobkin, S. Granholm
Reviewed by: L. Mewaldt
Edited by: R. Duke
DISTRIBUTION, ABUNDANCE, AND SEASONALITY
A common resident of desert riparian and desert
wash habitats in lower Colorado River
Valley; also fairly common in Imperial and Coachella valleys.
Frequents dense vegetation;
thickets of willow, cottonwood, mesquite, saltcedar (Davis 1951, Marshall
1960). Occurs in
brush in yards and orchards at Brock Ranch, southern Imperial Co. (Garrett
and Dunn 1981).
SPECIFIC HABITAT REQUIREMENTS
Feeding: Takes insects and seeds from
ground and low in shrubs (Laudenslayer 1981).
Scratches in litter and gleans from ground and shrubs, often in shade.
Cover: Davis (1951) reported mesquite,
willow, and arrowweed most important in
providing cover. Also uses saltcedar (Garrett and Dunn 1981)
and quailbush (Grinnell and
Miller 1944).
Reproduction: Builds nest in desert riparian
vegetation, especially willow and mesquite.
Nest usually 2-10 m (6-30 ft) above ground.
Water: Makes extensive use of water when available (Dawson 1954).
Pattern: Requires dense riparian thickets
or tracts of desert wash brush, especially willow
for breeding and mesquite for cover. Feeds under, between, and
in shrubs.
SPECIES LIFE HISTORY
Activity Patterns: Yearlong, diurnal activity.
Seasonal Movements/Migration: None reported.
Home Range: Home range encompasses, but
is somewhat larger than, breeding territory
(Marshall 1960). Laudenslayer (1981) reported density of 4.5
pairs per 40 ha (100 ac) in
screwbean mesquite-saltcedar habitat in Arizona; Anderson and Ohmart
(1977) reported
density of 12.3 per 40 ha (100 ac) in similar habitat. Austin
(1970) reported a density of 2-4
breeding pairs per 40 ha (100 ac) in bosque habitat in southern Nevada.
Territory: In Arizona, territory varied
from 1.1 to 2.6 ha (2.7 to 6.4 ac) (Marshall 1960).
Laudenslayer (1981) reported territory of 1.4 to 2.5 ha (2.76 to 6.1
ac) along the lower
Colorado River.
Reproduction: Nests from late February
into early August. Clutch size 2-4 eggs, usually
3 (Bent 1968). According to Cooper (1870), raises 2 or more broods
per season. Incubation
12-13 days; young may hatch asynchronously. Female broods altricial
young, which leave
nest in about 2 wk.
Niche: A common cowbird host. May
form long-term pair bond on a permanent territory.
Cowbird parasitism and habitat degradation and loss apparently reducing
numbers in recent
decades (Ehrlich et al. 1988).
REFERENCES
Anderson, B. W., and R. D. Ohmart. 1977. Wildlife use and
densities report of birds and
mammals in lower Colorado river Valley.
U.S. Dep. Inter., Bur. Reclamation Rep. Contract
No. 7-07-30-V0009.
Austin, G. T. 1970. Breeding birds of desert riparian habitat
in southern Nevada. Condor
72:431-436.
Bent, A. C. (O. L. Austin, Jr., ed.). 1968. Life histories
of North American cardinals,
grosbeaks, buntings, towhees, finches, sparrows,
and allies. 3 Parts. U.S. Natl. Mus.
Bull. 237. 1889pp.
Cooper, J. G. 1870. Geological survey of California.
Ornithology. Vol. 1. Land Birds.
Harvard Univ. Press, Cambridge, MA.
592pp.
Davis, J. 1951. Distribution and variation of the brown
towhees. Univ. Calif. Publ. Zool.
52:1-120.
Dawson, W. R. 1954. Temperature regulation and water requirements
of the brown and
Abert towhees, Pipilo fuscus and Pipilo aberti.
Univ. Calif. Publ. Zool. 59:81-124.
Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1988. The birder's
handbook. Simon and
Schuster, New York. 785pp.
Garrett, K., and J. Dunn. 1981. Birds of southern
California. Los Angeles Audubon Soc.
408pp.
Grinnell, J., and A. H. Miller. 1944. The distribution
of the birds of California. Pac. Coast
Avifauna No. 27. 608pp.
Laudenslayer, W. F., Jr. 1981. Habitat utilization by birds
of three desert riparian
communities. Ph.D. Thesis, Arizona State
Univ., Tempe. 148pp.
Marshall, J. T., Jr. 1960. Interrelations of Abert and
brown towhees. Condor 62:49-64.
Compiled from California Department of Fish and Game - California Interagency Wildlife Task Group