Measurements
Both Sexes
- Length
- 5.1–5.9 in
13–15 cm - Wingspan
- 7.9 in
20 cm - Weight
- 0.6–0.6 oz
17–18 g
Other Names
- Bruant de Cassin (French)
- Zacatonero de Cassin (Spanish)
Cool Facts
- In his display flight, the male Cassin's Sparrow flies straight up and then floats downward on fixed wings, singing the entire time. This behavior, distinctive among sparrows, is sometimes called "skylarking."
- Cassin's Sparrow population numbers vary widely in response to summer rainfall. In some years singing males suddenly appear at the edge of the range where none usually breed. Just what causes these movements is unknown, but hypotheses include east-to-west migration, dispersal of birds that were unsuccessful breeding in another area, and nomadism.
- Cassin's Sparrow has an unusual molt cycle. The juvenile molts twice in the first six months of life whereas the adult has a long body molt lasting several months, then a much quicker complete molt in fall.
Habitat
Grassland
Arid grasslands with scattered small trees and shrubs.
Food
Insects
Insects (during the breeding season) and seeds.
Nesting
Nesting Facts
- Clutch Size
- 3–5 eggs
- Egg Description
- White and unmarked.
- Condition at Hatching
- Helpless with tufts of gray down.
Nest Description
Open cup of grass and other fibers, lined with fine grasses and horsehair. Located on or near the ground in grass clump or low shrub.
Nest Placement
Ground
Behavior
Ground Forager
Territorial male Cassin's Sparrow flies up to a height of 2-6 meters (6.6-19.7 ft), or sometimes as high as 12-15 meters (39-49 ft), uttering quiet first notes of song. Then he floats down on stiff wings, with tail fanned and legs dangling, while completing the song.Feeds almost entirely on the ground.
Conservation
Least Concern
Grazing and clearing of land may pose a concern. At present, Cassin's Sparrow population numbers are considered to be relatively secure, but it appears to be decreasing in some areas.
Credits
- Dunning, J. B., Jr., R. K. Bowers, Jr., S. J. Suter, and C. E. Bock. 1999. Cassin's Sparrow (Aimophila cassinii). In The Birds of North America, No. 471 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.