The Marbled Godwit is a large, long-legged shorebird with very long, slightly upturned bicolored bill and bright cinnamon underwings and remiges. Overall length 42 to 48 cm with bill 8 to 13 cm; mass 285 to 454 g. In breeding plumage generally tawny buff in coloration (looks darker brown above and lighter buff below from a distance); upperparts speckled and barred with dark brown and black; underparts tawny with fine dark streaks on neck and upper breast and black barring on sides, flanks and belly; bill bright pink to orange on basal half; legs long and gray or blue-gray. Does not show well-marked seasonal plumage change, and nonbreeding plumage is similar to breeding plumage except underparts paler tawny and essentially unbarred, and base of bill paler and more extensively pink. Sexes are alike in appearance throughout year, but female is larger than male with a noticeably longer bill (Gratto-Trevor 2000).
For a comprehensive review of the conservation status, habitat use, and ecology of this and other Montana bird species, please see Marks et al. 2016, Birds of Montana.
Western Hemisphere Range
In the Bozeman area normal migration periods are from May 3 to May 20 and September 1 to September 25, with peaks on May 10 and September 15.
Breeds in short, sparsely to moderately vegetated landscapes that include native grassland and wetlands. Individuals in North Dakota preferred ephemeral ponds (normally dry by 1 May), as well as temporary ponds and alkali wetland. Semi permanent ponds often used as well. Upland habitat during breeding season primarily idle grassland and pastures; tilled land avoided, but hay fields used in proportion to availability. During migration will flock around variety of wetland types (Gratto-Trevor 2000).
In winter and at coastal sites, polychaetes, small bivalves, crabs, and earthworms. In interior staging areas and breeding grounds, insects (particularly grasshoppers, aquatic plant tubers, leeches, and small fish (Gratto-Trevor 2000).
Male selects nest site and initiates scrape. Nests on ground, often situated in native prairie considerable distance from water. Eggs are ovate pyriform in shape and pale buff or olive in color sparsely marked with blotches and scrawls. Clutch size almost always 4, range 3 to 5 eggs (Gratto-Trevor 2000). Egg dates are probably similar to those reported for North Dakota: April 17 to June 22.