Look for Rufous-crowned Sparrows on dry, open hillsides covered with grasses, rocks, and scattered shrubs, including coastal sagebrush, open chaparral, scrub oaks, pinyon pine, and other woody plants. Dense woody growth is unsuitable. They occur from sea level up to about 10,000 feet elevation (in Mexico). Periodic wildfire helps Rufous-crowned Sparrows by keeping the habitat open, and this species tends to be more common in areas that have burned in the past 15 years, according to data from California. Back to top
Rufous-crowned Sparrows eat mainly insects in spring and summer, and mainly stems, shoots, and seeds in winter. They tend to walk or hop, pecking or scratching at the ground under the protective cover of shrubs or dense grasses; occasionally taking to shrub and tree branches. Insect prey includes crickets, grasshoppers, ground beetles, scale insects, and ants. Plant food includes wild oats, chickweed, knotweed, pigweed, and parts of other herbaceous plants.Back to top
They usually build their nests on the ground or in a small depression; occasionally near the base of a shrub up to about 1.5 feet off the ground. Nests are often well concealed under grass, leaves, or rocks.
The female builds the nest, which is a thick, loose cup made of dried grasses and rootlets with a few twigs or bark strips. She lines the nest cup with fine grasses and horse, deer, or other animal hair. When finished the nest is about 4 inches across and 2.5 inches tall, with an inner cup that is about 2.5 inches across and 1.5 inches deep.
|Clutch Size:||2-5 eggs|
|Number of Broods:||1-2 broods|
|Egg Description:||Bluish white to white, without spots.|
|Condition at Hatching:||Naked, with eyes closed.|
Rufous-crowned Sparrows are wary birds that stay close to the ground among shrubs or grasses, often running to escape danger rather than flying. They are weak fliers. When defending their territories, males stiffen their bodies, droop their wings, fluff out their feathers and raise their tail about 45 degrees. When protecting their nests, Rufous-crowned Sparrows may drop off the nest or a nearby bush, feign injury with a “broken wing” display, or scurry along the ground away from the nest in hopes of distracting the predator. They chase away other Rufous-crowned Sparrows and occasionally a few other species, including Mexican Jays, Painted Bunting, Lazuli Bunting, California Towhee, and Spotted Towhee. The species is not just nonmigratory; it tends to stay on its territory and does not group up into large winter flocks the way many sparrows do. They seem to be monogamous through the breeding season and may remain in pairs year-round. Mexican Jays and rattlesnakes are likely predators of eggs, young, and possibly adults.Back to top
Rufous-crowned Sparrows are fairly numerous and widespread, but their numbers declined by 45% between 1966 and 2014, according to the North American Breeding Bird Survey. Partners in Flight estimates a global breeding population of 2 million individuals, with 54% of the population living in the U.S. and 46% in Mexico. The species rates an 11 out of 20 on the Continental Concern Score. Rufous-crowned Sparrows is not on the 2014 State of the Birds Watch List. These sparrows depend on a fairly specific set of habitat requirements, which renders them vulnerable to habitat degradation and fragmentation. Suppression of natural wildfires has allowed their open scrub habitat to grow into dense stands that are unsuitable for this species. Evidence from California suggests that habitat remains suitable for Rufous-crowned Sparrows for up to 15 years after a fire, but becomes less suitable thereafter. Development of their hillside habitat into subdivisions and avocado or lemon orchards has also removed some of their habitat from the landscape. There are suggestions that grazing and trampling by cattle can open up dense habitat and make areas more suitable for Rufous-crowned Sparrows.Back to top
Collins, Paul W. 1999. Rufous-crowned Sparrow (Aimophila ruficeps), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
Dunne, Pete. 2006. Pete Dunne's essential field guide companion: Houghton Mifflin Harcourt.
Ehrlich, P. R., D. S. Dobkin and D. Wheye. 1988. The birder's handbook. A Field Guide to the natural history of North American birds, including all species that regularly breed north of Mexico. New York: Simon and Schuster, Inc.
Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.
North American Bird Conservation Initiative. 2014. The State of the Birds 2014 Report. US Department of Interior, Washington, DC, USA.
Partners in Flight. 2017. Avian Conservation Assessment Database. 2017.
Sauer, J. R., J. E. Hines, J. E. Fallon, K. L. Pardieck, Jr. Ziolkowski, D. J. and W. A. Link. The North American Breeding Bird Survey, results and analysis 1966-2013 (Version 1.30.15). USGS Patuxtent Wildlife Research Center 2014b. Available from http://www.mbr-pwrc.usgs.gov/bbs/.
Sibley, David Allen. 2014. The Sibley guide to birds, second edition. Alfred A Knopf, New York.