American Tree Sparrow

American Tree Sparrow

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1. Description
2. Sound
3. Conservation Status
4. Other Names
5. Cool Facts
6. Full detailed species account

The American Tree Sparrow is a common winter visitor in backyards all across southern Canada and the northern United States. Despite its common name, it forages on the ground, nests on the ground, and breeds primarily above treeline in the far North.

Description

• Small songbird.
• Rusty brown crown and eyestripe on gray head.
• Dark spot in center of unstreaked breast.
• Two white wingbars.
• Tail rather long.

• Size: 14 cm (6 in)
• Wingspan: 24 cm (9 in)
• Weight: 13-28 g (0.46-0.99 ounces)

Sex Differences

Sexes alike.

Sound

Song a series of thin, high, sweet whistled notes. Call a hard "tseet."

Conservation Status

Common. Remote breeding areas little affected by people. Uses human-modified habitats readily in winter.

Other Names

Bruant hudsonien (French)

Cool Facts

• During the summer, the American Tree Sparrow eats nearly 100% animal matter (mostly insects). In the winter it eats none, turning then to eating entirely seeds and other plant foods.
• As in most birds, the American Tree Sparrow is sensitive to changes in day length, which influence the growth of the sex organs. Increasing day length in late winter causes the gonads to grow. This sensitivity to light is independent of vision. Blind tree sparrows in captivity still show normal patterns of gonadal growth when kept in the proper light conditions.

• No one knows just how many American Tree Sparrows exist. But they breed across a vast expanse of northern Canada and Alaska, approximately 100 million hectares (247 million acres). If the area is about 10-20% filled by tree sparrows, and they have 1-ha territories, as is the case near Churchill, Manitoba where they have been well studied, then approximately 10 to 20 million pairs should be breeding.

• A study found that the American Tree Sparrow seems to prefer to look for predators out of its left eye. This preference may be because the right hemisphere of the brain is dominant for processing visual information. Oddly, the Dark-eyed Juncos examined in the same study preferred to look out of their right eyes.

Sources used to construct this page:

1. Franklin, W. E., III, and S. L. Lima. 2001. Laterality in avian vigilance: Do sparrows have a favourite eye? Animal Behaviour 62: 879-885.
2. Naugler, C. T. 1993. American Tree Sparrow (Spizella arborea). In The Birds of North America, No. 37 (A. Poole, P. Stettenheim, and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C.