Field Sparrow Life History

Habitat

Field Sparrows seek out open habitat with low perches, such as abandoned agricultural fields and pastures, fencerows, road and forest edges, and openings in wooded areas. You may also spot them occasionally in Christmas tree farms, orchards, and nurseries. They’ll breed in fields that were recently burned or cultivated as long as there are some trees or other perches available, but will abandon such settings as thickets of trees grow back. Shy around human habitation, Field Sparrows avoid breeding near where people live. In winter, look for them in settings similar to their summer habitats: abandoned fields and pastures, forest edges, and fencerows. In migration they’ll occasionally turn up in suburban yards.Back to top

Food

Field sparrows eat mainly grass seeds in winter, then switch to a blend of seeds and insect prey as the weather warms. Their small bills limit them to small seeds, including those of crabgrass, panic grass, foxtail, and horseweed. Insects make up about half of the summer diet. Prey includes butterflies, weevils, beetles, grasshoppers, cicadas, and spittlebugs, as well as spiders and snails. Parents feed nestlings a diet of spiders and insects, including caterpillars, grasshoppers, flies, bees, and beetles. Back to top

Nesting

Nest Placement

Female Field Sparrows examine several potential nest sites before settling on a location. In spring, nests are often built on the ground in a clump of grass or at the base of a shrub, where they’re less visible. Once grasses get taller and bushes and trees begin to leaf out, Field Sparrows build subsequent nests a foot to as much as 10 feet off the ground, where they’re less accessible to snakes and other predators. Nest sites include blackberry bushes, stands of St. John’s wort, honeysuckle, and coralberry, as well as in dogwood, redcedar, hawthorn, and elms. Field Sparrows avoid human habitation when selecting a nest site.

Nest Description

Only the female Field Sparrow builds the nest, although her mate may help by offering nesting material. Working mainly from early to late morning, she first weaves a framework of crisscrossed grass stems, then constructs an open cup combining coarse and fine grasses lined with grass, rootlets, and hair. It takes 5–8 days to build the season’s first nest; subsequent nests take only 2–3 days to complete. The finished nest measures 3.3 to 8.3 inches across and 1.9 to 4.3 inches high, with a cup depth ranging from 1 to 2.4 inches.

Nesting Facts

Behavior

Field Sparrows hop on the ground as they forage for seeds and insects, often near shrubs or other cover. Like other small sparrows, they have a distinctive style of feeding on grass seed heads: a bird flies to the top of a tall grass stem, then uses its weight to “ride” the stem to the ground, where it pins the seed head and plucks individual seeds. Field Sparrows also pounce on insect prey from low perches. Male Field Sparrows arrive on the breeding grounds 10 to 20 days ahead of females and set up exclusive territories, often spending hours chasing other males along disputed boundaries. Pairs form within a day or two of the females’ arrival. Although Field Sparrows are almost always monogamous, first-time breeding males that form pairs late in the season may end up feeding a nestling that was fathered by a different male. Following the breeding season, Field Sparrows form loose flocks that winter in fallow fields, pastures, and along roads and forest edges.Back to top

Conservation

Field Sparrows are common, although their populations have dropped considerably in the last 53 years. Between 1966 and 2019, the North American Breeding Bird Survey shows a decline of over 2% per year, for a cumulative decline of approximately 69%. Partners in Flight estimates the global breeding population at 9.3 million and rates them 12 out of 20 on the Continental Concern Score, indicating a species of relatively low conservation concern. However, it is included in the list of Common Birds in Steep Decline, for species that are still too numerous or widely distributed to warrant Watch-List status but have been experiencing troubling long-term declines.

The North American Breeding Bird Survey records an average increase in only one region of North America: the Prairie Pothole Region. This may be due to the grassland habitat protection efforts of the Conservation Reserve Program, funded by the Farm Bill. Field Sparrows tend not to nest in human-dominated landscapes such as tilled agricultural fields and suburbs. In recent decades, the great expansion of human development has likely permanently reduced Field Sparrow breeding habitat, which can best be maintained by protecting some woody vegetation in fields undergoing succession, and by thinning shrubs and saplings in forested habitat to maintain openings.

Credits

Carey, Michael, D. E. Burhans and D. A. Nelson. (2008). Field Sparrow (Spizella pusilla), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Evans, F. C. (1964). The food of Vesper, Field, and Chipping sparrows nesting in an abandoned field in southeastern Michigan. American Midland Naturalist 72:57-75.

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.

Rosenberg, K. V., J. A. Kennedy, R. Dettmers, R. P. Ford, D. Reynolds, J. D. Alexander, C. J. Beardmore, P. J. Blancher, R. E. Bogart, G. S. Butcher, A. F. Camfield, A. Couturier, D. W. Demarest, W. E. Easton, J. J. Giocomo, R. H. Keller, A. E. Mini, A. O. Panjabi, D. N. Pashley, T. D. Rich, J. M Ruth, H. Stabins, J. Stanton, and T. Will (2016). Partners in Flight Landbird Conservation Plan: 2016 Revision of Canada and Continental United States. Partners in Flight Science Committee.

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.

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