Limosa fedoa (Linnaeus, 1758)
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Basis for Listing
The marbled godwit is a large shorebird that breeds in the prairie pothole region of the northern United States and southern Canada. It winters in North, Central, and South America, mainly in coastal areas. During the breeding season, marbled godwits prefer native grasslands with short vegetation adjacent to a variety of ephemeral and semi-permanent wetlands (Ryan et al. 1984; Gratto-Trevor 2000). In presettlement times, Roberts (1932) considered the marbled godwit abundant and widespread throughout the western prairies of Minnesota and thought that at one time it may even have extended into the prairies of the southeastern quarter of the state. Breeding, however, had only been documented from counties north of the Minnesota River Valley. Following a trip to Grant County in 1879, Roberts commented that the godwit "was so abundant, so constant and insistent ... and so noisy that it became at times an actual nuisance". But, by the turn of the century, when native grasslands came under cultivation, the marbled godwit began to decline. Adding to its demise was the excessive slaughter by market hunters in the late 1800s and early 1900s.
The marbled godwit is most readily distinguished from other shorebirds by its large size (40-50 cm (15.7-19.7 in.) long) and its very long (8-13 cm (3.1-5.1 in.)), slightly upturned bill. It is largely brownish in coloration, with mottled upperparts, including its rump, and barred underparts. Cinnamon-colored wing linings are also diagnostic. The Hudsonian godwit (Limosa haemastica), a non-breeding migrant in Minnesota, differs in having a distinctive white rump. The long-billed curlew (Numenius americanus), now extirpated as a breeding bird in Minnesota, is of similar coloration and size, but has a long, decurved bill. The marbled godwit tends to be rather noisy and conspicuous on breeding grounds, often flying toward, rather than away from an intruder.
Marbled godwits prefer native grasslands with sparse to moderate cover, adjacent to a complex of wetlands. Nesting occurs in short upland grasslands or in cropland stubble that is within or close to large expanses of grassland. Intensively tilled land is avoided (Ryan et al. 1984). Marbled godwits feed along the edges of semi-permanent and seasonal wetlands (Ryan et al. 1984). Often these edges have been grazed, which results in short cover and a possible enhancement of invertebrate populations due to nutrient enrichment by livestock manure. Moist grasslands that have been burned or hayed are also important feeding sites. In Minnesota, typical marbled godwit habitat consists of extensive, moderately-grazed pasture or wet prairie interspersed with scattered pockets of sedge fen, or wet roadside ditches. Large areas of such habitat occur in the Tallgrass Aspen Parklands Province of far northwestern Minnesota, where marbled godwits are relatively common.
Biology / Life History
The marbled godwit is a long-distance migrant that breeds in the Great Plains of North America, and winters mainly in coastal mudflats, estuaries, or beaches of North, Central, and South America (Gratto-Trevor 2000; NatureServe 2008). During migration and throughout the wintering season, marbled godwits join flocks of other large shorebirds (Gratto-Trevor 2000), and may roost in large groups (NatureServe 2008). Marbled godwits may also nest in semicolonial groups, with nests as close as 60 m (197 ft.) to one another (Gratto-Trevor 2000). Marbled godwit pairs are monogamous over subsequent years. Pairs form during a courtship display that involves ground-chasing behavior and a variety of ceremonial flights. The male chooses a dry, upland nest site by scraping the ground, and the female accepts or rejects this site. Both birds then create the nest during an elaborate scraping ceremony. The final nest is a shallow cup with a sparse lining of grasses. Females lay 4 eggs, and both sexes participate in incubation. When chicks emerge after 23-26 days, they are precocial and able to feed themselves. Chicks fledge 26-30 days after hatching (Gratto-Trevor 2000). Marbled godwits feed mainly on invertebrates. In prairies and other grasslands, grasshoppers and other insects are common food. Mollusks, crustaceans, and worms are eaten in coastal areas. Marbled godwits also feed on tubers, seeds, and other plant materials (Gratto-Trevor 2000; NatureServe 2008). During migration, sago pondweed (Stuckenia pectinata) tubers may comprise a majority of the marbled godwit's diet (Gratto-Trevor 2000).
Conservation / Management
The marbled godwit generally prefers large habitat units that include native grasslands or pastures, and both semi-permanent and ephemeral wetlands (Ryan et al. 1984). Because grasslands are becoming increasingly fragmented, preservation of large units is important for the conservation of this species. Prairies have evolved with periodic disturbance from fire and grazing animals. Prairies in private ownership are often grazed or hayed, keeping the grasses relatively short (less than 15 cm (6 in.)). The birds use such short, grassy cover for feeding and nesting in spring and summer. The use of fire, grazing, and/or mowing in grassland management is needed to maintain high quality habitat for marbled godwits (Ryan et al. 1984). Degradation of coastal areas can also have a detrimental effect on marbled godwit populations. Protecting shorebird habitat in the Americas from development and disturbance could benefit this species (Gratto-Trevor 2000). Several new resources including a conservation plan for marbled godwits (Melcher 2006) and a model to predict habitat suitability (U.S. Fish and Wildlife Service 2008) have recently been developed and can be used to guide conservation efforts including habitat management, restoration, environmental review, and where to concentrate funds from habitat protection programs such as the Wetlands Reserve Program.
Conservation Efforts in Minnesota
The Minnesota Biological Survey (MBS) has conducted bird surveys in most of the marbled godwit's breeding range in the state. Observations by MBS have provided useful information about habitats commonly used by the marbled godwit in Minnesota. Preferred areas include hayfields, pasture, grassy ditches, open sedge fens, grasslands, and agricultural fields. More scientific study is needed, however, to determine which features (or combination of features) promote breeding success. Preservation and management of areas containing these features could then be pursued. Continuing surveys to monitor abundance and determine marbled godwit population trends are also needed (Gratto-Trevor 2000).
Gratto-Trevor, C. L. 2000. Marbled Godwit (Limosa fedoa). Number 492 in A. Poole and F. Gill, editors. The birds of North America. The Birds of North America, Inc., Philadelphia, Pennsylvania.
Melcher, C. P., A. Farmer, and G. Fernandez. 2006. Version 1.1. Conservation Plan for the Marbled Godwit. Manomet Center for Conservation Science, Manomet, Massachusetts. 114 pp.
NatureServe. 2008. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.0. NatureServe, Arlington, Virginia. <http://www.natureserve.org/explorer>. Accessed 3 June 2008.
Roberts, T. S. 1932. The birds of Minnesota. 2 volumes. University of Minnesota Press, Minneapolis.
Ryan, M. R., R. B. Renken, and J. J. Dinsmore. 1984. Marbled Godwit habitat selection in the northern prairie region. Journal of Wildlife Management 48:1206-1218.
U.S. Fish and Wildlife Service. 2008. Expert model for Marbled Godwit landscapes [web application]. Version 2.0. U.S. Fish and Wildlife Service, Habitat and Population Evaluation Team, Fergus Falls, Minnesota. <http://www.fws.gov/midwest/hapet/GodwitModel.htm>. Accessed 5 November 2008.