American Goldfinch

Spinus tristis
STANFORD LOCATIONS:

Fairly common migrant and winter resident in various habitats virtually throughout campus. Often forages in flocks (occasionally at feeders) during the nonbreeding season.
  
Nest
Location
Nest
Type
Eggs
Mating System
Dev.
Parental Care
Primary &
2ndary Diet
Foraging
Strategy
F
I: 10-12 DAYS
ALTRICIAL
TREE
 1' - 30' (To 60')
F
4-6
(3-7)
F: 11-17 DAYS
MF
INSECTS
GROUND GLEAN
BREEDING: Weedy and cultivated fields, open decid and riparian woodland. Occ 2 broods.
DISPLAYS: Male song-flight on level (rather than typical undulating) flight, rapidly flapping wings.
NEST: In branch fork, often woven so tightly that nest holds water; of forbs, other pliable veg, lined with plant down. Caterpillar webbing and spider silk often used to bind outer rim. Male may collect some nest material and give to female.
EGGS: Pale blue or bluish-white, unmarked. 0.6" (16 mm).
DIET: Includes seeds of decid trees, forbs (esp composites), grass, floral buds, berries. Young fed regurgitant of milky seed pulp; few insects.
CONSERVATION: Winters s to n Mexico (and along coast to Veracruz). Common cowbird host. Declined in n e as House Sparrows increased.
NOTES: Commonly change mates between years; females show nest-site tenacity. Nests usu near water. Male feeds female on nest; female may call to male to be fed, begs when he appears with food. Females may sit on eggs 95% of the time! Hatching asynchronous, increasingly so as season progresses. Late nester except in CA and s w; older birds nest earlier than younger birds. Winter flocks up to 300 common, often with siskins, redpolls.
ESSAYS: Bird Biology and the Arts; Site Tenacity; Mixed-Species Flocking; Incubation Time; Incubation: Heating Eggs; Brood Reduction; Cowbirds.
REFERENCES: Middleton, 1978, 1979; Skagen, 1987.

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Except for Stanford Locations, the material in this species treatment is taken, with permission, from The Birder's Handbook (Paul Ehrlich, David Dobkin, & Darryl Wheye, Simon & Schuster, NY. 1988).