Thick-billed Longspur Identification Guide

Key Field Marks

• Size & shape: A stocky, sparrow-sized bird, 14–16 cm, with a notably heavy, thick conical bill (the source of its name) and a short tail.
• Breeding male: Gray head with a black crown patch, a bold black crescent across the breast, chestnut lesser wing coverts, and pale gray underparts.
• Female / nonbreeding / winter: Much plainer and streaky buffy-brown overall, with the thick pale bill remaining a useful structural clue even when plumage is nondescript.
• Tail pattern (best flight mark): Mostly white tail with a dark central stripe and dark tip forming an inverted-T or anchor shape — visible as birds flush and fly off, and the single best field mark for separating longspur species in flight.

Separating Thick-billed Longspur from Similar Species

• Chestnut-collared Longspur: Shows a different white tail pattern (white restricted more to the sides with a dark triangle rather than a centered inverted-T), a chestnut collar on breeding males, and a slimmer bill.
• Lapland Longspur: Larger, with a rustier nape patch in breeding males and a different, less extensively white tail; found in a broader range of open habitats including agricultural fields, not just shortgrass prairie.
• Horned Lark: Similar open-country habitat but lacks the longspur's stubby thick bill and white-anchor tail pattern, and shows black facial markings and "horns" instead.

Where and When to See One

• Range: Breeds in shortgrass prairie of the northern Great Plains, from Montana and the Dakotas north into southern Alberta and Saskatchewan.
• Habitat: Requires very short, sparse grassland, often heavily grazed prairie, differing from the slightly taller grass preferred by Chestnut-collared Longspur.
• Season: Breeds spring through summer; winters in shortgrass and agricultural fields of the southwestern United States and northern Mexico, often in loose flocks with other longspur species.

Voice

• Males give a bubbly, tinkling flight song reminiscent of a lark's, delivered during a butterfly-like display flight where the bird rises and glides down on stiffly held wings; call notes include a dry rattle.