The Chestnut-collared Longspur is one of the most colorful birds of the prairies and, where common, it animates grasslands with its undulating flight display and melodic song. As an endemic of the North American Great Plains, the species historically bred at sites disturbed by fire or grazed by a diversity of herbivores until the late Pleistocene, after which grazing was primarily by bison species (genus Bison). The Chestnut-collared Longspur generally avoids nesting in areas protected from grazing or other disturbances that maintain short, sparse vegetation. Breeding territories are sometimes clumped together, so this species may at times be locally abundant; but as native prairie has disappeared, so has the Chestnut-collared Longspur. Estimates suggest the species population has declined by more than 87% since the 1960s (Sauer et al. 2015). Breeding populations in Nebraska and Minnesota, have been much reduced, and this species no longer breeds in Kansas, where it was described as abundant in the 1870s.
In fall, this species moves south from its breeding grounds in the northern Great Plains and prairies of Canada to winter primarily in the short-grass prairie and desert grasslands of the southern United States and northern Mexico. Wintering flocks reaching densities as high as 166 individuals per hectare feed on grains such as wheat and on the seeds of native grasses.
The male Chestnut-collared Longspur defends its territory by performing Aerial Song Displays—flying upward to a height of 10 to 15 meters, then spreading its tail and singing during descent. Male plumage is conspicuous with black belly and cap, deep chestnut collar, and yellow cheek. The buff-colored female, by contrast, blends cryptically into its prairie habitat. Double-brooded and socially monogamous, this is one of many species in which extra-pair copulations are known to occur. Most extra-pair young are found in second-brood nests.
Some aspects of the biology and natural history of Chestnut-Collared Longspurs are reasonably well understood, including habitat associations, reproductive success, and response to management on breeding grounds. Many gaps remain, however, in our knowledge of this species' migratory and wintering biology, physiology, area sensitivity, conspecific attraction, and responses to industrial disturbances.