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Field
Guide IDs: BREEDING:
Habitat generalist:
wide range of open and partly open habitats,
abundant in suburbs. 2 broods, occ 3 or
4. DISPLAYS:
Male and female
perform mating "dance" facing each other with heads
and tails high, darting at each other and
retreating; may also serve as territorial display,
often occurring between males. NEST:
Usu in conif or
decid shrub, also occ in vines; of twigs, lined
with grass, rootlets. Male usu builds foundation,
female lines it. Built in 4-8 days. EGGS:
Blue-green, usu
heavily marked with browns. 1.0" (24
mm). DIET:
Includes crayfish,
sowbugs, snails, few small vertebrates; berries.
Nestlings fed mosty insects, some fruit. CONSERVATION:
In winter largely
resident; few migrate s to s Mexico, Bahamas,
Greater Antilles. Rare Brown-headed Cowbird host,
occ Bronzed Cowbird host. NOTES:
Uses songs and
calls of other birds; unmated males sing more than
mated males, only unmated males sing at night in
spring. Vigorously defends territory against many
other species. Long-term pair bond; polygyny and
polyandry rare. Young brooded up to 4 days, almost
entirely by female. Male assumes feeding of
fledglings while female renests. Conspicuous
"wing-flashing" ostensibly functions to stir up
insects and to distract predators, esp snakes.
Sexes often defend separate winter feeding
territories. Common to abundant
resident throughout campus, nesting and foraging in
a variety of habitat types. Did not occur on campus
historically, but populations from southern
California expanded northward throughout this
century. One on campus in 1893 may have been the
first record from the San Francisco Bay
area. ESSAYS: Vocal
Copying;
Vocal
Development;
Natural
Selection;
Bathing
and Dusting;
Birds,
DNA, and Evolutionary
Convergence;
Visual
Displays REFERENCES:
Breitwisch and
Whitesides, 1987; Breitwisch et al., 1986; Laskey,
1962; Logan, 1983. |
