Thick-billed Longspur

The Thick-billed Longspur is a shortgrass prairie specialist named for its notably heavy, conical bill, larger and stouter than that of other longspur species. This is the currently accepted English name, adopted by the American Ornithological Society in 2020 to replace the former name, McCown's Longspur, which honored a 19th-century army officer; the scientific name and the bird itself remain the same.

Breeding males are gray overall with a black cap, a black crescent-shaped patch across the breast, and a chestnut patch on the shoulder. Females and nonbreeding birds are considerably plainer, streaky brown overall, but the thick bill remains a useful identification clue year-round.

The species favors especially short, sparse, or heavily grazed grassland, often shorter than the grass preferred by the similar Chestnut-collared Longspur breeding in the same region.

Key Field Marks

• Notably thick, conical bill, the namesake feature, heavier than in any other longspur
• Breeding male: gray body, black cap, black crescent across the breast, chestnut shoulder patch
• Tail pattern: white with a black shape resembling an inverted T or anchor

Similar Species

• Chestnut-collared Longspur: slimmer bill, a simple black terminal tail band rather than an anchor-shaped pattern, and black underparts with a chestnut nape collar in breeding males rather than a breast crescent

Bill thickness and tail pattern together are the most reliable field marks distinguishing this species from other longspurs sharing shortgrass prairie habitat.

The Thick-billed Longspur breeds in shortgrass prairie of the northern Great Plains, including Montana, Wyoming, the Dakotas, and adjacent southern Canada, favoring the sparsest and shortest grass available, often in heavily grazed pasture.

In winter, the species moves to open grassland and agricultural fields of the southwestern United States and northern Mexico. Like other shortgrass prairie specialists, it has experienced population declines linked to the conversion of native prairie to cropland.

Behavior

Thick-billed Longspurs forage and nest on open, sparsely vegetated ground, and often gather in loose flocks outside the breeding season, sometimes with other prairie songbirds.

Voice

The song is a melodic, tinkling warble, delivered during a brief aerial display over the prairie.

Feeding

Diet includes seeds and insects gathered from open ground, with insects especially important for feeding nestlings during the breeding season.

Nesting and Breeding

The nest is a shallow cup built directly on bare or sparsely vegetated ground, often in areas so heavily grazed that little cover remains. Clutches typically contain 3-4 pale eggs with dark markings.