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Fox Sparrow Life History


ForestsFox Sparrows breed in thickets and chaparral across northern North America and south along the western mountains. Each of the four main types of Fox Sparrow (see Regional Differences) has its own preferences when it comes to vegetation. “Red” Fox Sparrows live in scrubby, brushy woods and forest edges (containing black spruce, white spruce, balsam fir, tamarack, aspen, birch, willow, and alder) from Alaska to Newfoundland, reaching into the northwestern corner of Maine. They winter in densely thicketed habitats across eastern North America, from Newfoundland to Minnesota to Texas to Florida, and in small numbers farther west. “Sooty” Fox Sparrows breed in deciduous streamside thickets (with willow and blackberry) along coastal Alaska and British Columbia from the Aleutian Islands to Washington, and winter in chaparral farther south along the Pacific Coast. “Slate-colored” Fox Sparrows breed in dense riparian thickets (of alder, water birch, willows, currants, gooseberries, and rose) from central British Columbia south to Colorado, and winter in tall chaparral from California to New Mexico. “Large-billed” Fox Sparrows nest in brushy fields at high elevations (with green-leaf manzanita, mountain whitehorn, and bush chinquapin) from western Oregon south into California and western Nevada, wintering in chaparral farther south in California. During migration, Fox Sparrows forage in the leaf litter of open hardwood forests as well as swampy thickets.Back to top


InsectsFox Sparrows forage on leaf litter and bare ground, usually under dense cover. During the breeding season they eat mainly insects—such as beetles, fly larvae, caterpillars, ants, bees, and scale insects. They find their prey with a characteristic “double-scratch” involving a hop forward and an immediate hop back, during which they simultaneously scratch both feet backwards through the leaf litter. (This foraging move is common among some sparrows and towhees.) They also eat other invertebrates (such as spiders, millipedes, and mollusks) along with seeds, fruits, or buds from plants such as strawberry, raspberry, blackberry, sedge, cinquefoil, buttonweed, serviceberry, pokeweed, red cedar, grape, witch hazel, ragweed, smartweed, and sorrel. During migration and winter, Fox Sparrows eat a more balanced mixture of plant and insect material.Back to top


Nest Placement

GroundFox Sparrows nest on the ground or in low crotches of bushes or trees. In Newfoundland they nest in or under conifers or among the roots of upturned stumps. In western North America, they nest in chaparral under dense, shrubby vegetation.

Nest Description

Their nesting behavior is not well known, but the female probably builds the nest on her own in 2–3 days. One female completed a new nest and laid an egg between sunrise and sunset of a single day. Nests vary a lot in size, from a few inches across to more than a foot across. The outer wall is made of twigs, strips of bark, shredded wood, rotting wood, broom moss, coarse dry grass, moss, and lichens. The inner cup is often lined with fine grass, rootlets, hair from sheep, cows, or dogs, feathers, moss, and sometimes fishing line.

Nesting Facts

Clutch Size:2-5 eggs
Number of Broods:1 brood
Egg Length:0.8-0.9 in (2.1-2.4 cm)
Egg Width:0.6-0.7 in (1.6-1.8 cm)
Incubation Period:12-14 days
Nestling Period:9-11 days
Egg Description:Pale bluish green, with bold splotches or cloudy markings of reddish brown.
Condition at Hatching:Helpless and downy.
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Ground ForagerFox Sparrows spend much of their time hopping on the ground and scratching though leaf litter as they forage for invertebrates. They rarely make long flights during their day-to-day activities. Within one day of arriving on the breeding grounds they establish territories of up to 2.5 acres in size, and they pair off with mates within a week. Outside of the breeding season, they usually spend their time alone or in small groups, and often associate with other sparrow species. Fox Sparrows are hunted by Merlins, Steller’s Jays and probably by other predatory birds; weasels, chipmunks, and snakes prey on nests. Parents will give a metallic chip and pretend to have a broken wing to lure potential predators (including people) away from their nests.Back to top


Low Concern

Fox Sparrows are numerous, and populations held steady between 1966 and 2019, according to the North American Breeding Bird Survey. Partners in Flight estimates a global breeding population of 35 million and rates them 10 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. Many Fox Sparrow nest in remote northern North America, and may be spared from human disturbance during the breeding period as these areas have few direct impacts from people. However, the distribution of Fox Sparrows has probably shifted because of logging and changes to forest fire regimes in the West. Both logging and forest fires create dense, shrubby regrowth that can serve as Fox Sparrow habitat.

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Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.

Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2019). The North American Breeding Bird Survey, Results and Analysis 1966–2019. Version 2.07.2019. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

Weckstein, Jason D., Donald E. Kroodsma and Robert C. Faucett. (2002). Fox Sparrow (Passerella iliaca), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

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