This large shorebird breeds primarily in the grasslands of the northern Great Plains, and winters in large numbers along the coast of southern California and western Mexico. Degradation of habitat, especially on its breeding grounds, is the major threat to Marbled Godwit.
Identification
Marbled Godwit is the largest of the four species of godwits found worldwide. As a group, godwits are distinguished from other shorebirds by their large size and their very long, upturned, bicolored bills. Among the godwits, Marbled is easily distinguished by its predominantly cinnamon-colored wings, tail, and underparts. Winter plumage is similar to the plumage found during breeding season, but is somewhat paler. Long-billed Curlew, which can be found in close proximity to Marbled Godwit on both its breeding and wintering grounds, is also a large, cinnamon-colored shorebird, but is easily distinguished from Marbled Godwit by the curlew's extremely long, downcurved bill.Distribution and Population Trends
Marbled Godwit breeds in three distinct areas across North America: the largest numbers nest in the grasslands of the northern Great Plains, primarily in Manitoba, Saskatchewan, Alberta, North Dakota, and Montana; a small population of 1,000 to 2,000 individuals breeds along the coast of southwestern James Bay, Ontario; and another small population of 1,000 to 3,000 birds nests in Alaska on the Alaska Peninsula. The species winters in greatest numbers along the Pacific coast from central California south to Mexico, although individuals can be found wintering as far north as Washington. On the Atlantic coast, Marbled Godwit winters regularly from North Carolina south to Florida. Along the Gulf Coast, the species is found in Florida, and then west from Louisiana to Texas and the north coast of the Yucatan Peninsula. A number of Important Bird Areas (IBAs) in both the United States and Canada help protect important habitat for Marbled Godwit. These sites include California's Morro Bay IBA, which regularly hosts over 2,000 wintering godwits; South San Francisco Bay IBA, a spot through which an estimated 10% of the global population of Marbled Godwit passes each spring; Saskatchewan's Luck Lake IBA, where up to 1,500 birds are reported during the summer; and Nunavut's Akimiski Island IBA, which likely provides migratory habitat for most (up to 1,500 birds) of the small James Bay breeding population.
The breeding range and population size of Marbled Godwit has decreased since 1900, with states such as Wisconsin, Iowa, and Nebraska no longer serving as breeding grounds. Trends taken from Breeding Bird Survey (BBS) data from 1966 to 2000 show no change in the overall population and an increase in the number of birds breeding in the United States. However, the BBS is not well suited to monitoring populations of the species because of the relatively low densities of birds on the breeding grounds, too few BBS routes in the major breeding areas, and possibly because of low detectability of non-vocalizing birds.Ecology
The major breeding population of Marbled Godwit nests in the prairies of the Great Plains, in landscapes composed of native grasslands with nearby marshes or ponds. Birds form monogamous pairs, with both sexes incubating a typical clutch of four eggs. The nest is placed on the ground, usually in a dry spot in short grass. Chicks are precocial--capable of walking and foraging on the same day as hatching. On the breeding grounds, insects (including grasshoppers) are a major source of food, while on coastal mudflat wintering grounds, mollusks, marine worms, crustaceans, and other invertebrates make up the bulk of a Marbled Godwit's diet. Following breeding, large flocks of Marbled Godwit form on the breeding grounds, with these flocks remaining together during migration.Threats
The major threat to Marbled Godwit is the degradation of its native grassland breeding habitat. The conversion of native grassland to agricultural land not only eliminates prime breeding habitat, it may also act as a population "sink," in which birds attempt nesting efforts but are usually unsuccessful. Many staging and wintering areas along the Pacific coast of the United States have been degraded or eliminated by development since 1800. In Mexico, recent development has created a new threat to important shorebird sites on the west coast of that country. Finally, the tendency of this species to flock during migration and wintering makes it vulnerable to both human-induced and natural catastrophes.Conservation
The U.S. Shorebird Conservation Plan lists Marbled Godwit as a "Species of High Concern," based on population trends, threats on breeding grounds, and threats on non-breeding grounds. Partners in Flight's Bird Conservation Plan for the Northern Mixed-grass Prairie, a physiographic area that supports almost 25% of the global population of Marbled Godwit, treats the species as one of the highest-priority species in the area. Montana's Bird Conservation Plan designates Marbled Godwit as a "Monitoring Species," meaning that Montana has a high responsibility to monitor the godwit's status and/or design conservation actions for the species. Finally, due to the concern that the Breeding Bird Survey is not an appropriate method for determining population trends for grassland birds such as Marbled Godwit, the Canadian Wildlife Service has begun a grassland bird monitoring program. It is hoped that this program will provide a more accurate assessment of grassland bird populations, and if so, that it will serve as a model for a future program monitoring American grasslands.
Audubon's San Francisco Bay Restoration Program is working to restore half of the estuary's wetlands and associated habitats over the next twenty years which provide a key migratory stop-over site for large numbers of Marbled Godwits. For more information visit: www.AudubonSFbay.org
What Can You Do?
Audubon's Important Bird Area program is a vital tool for the conservation of Marbled Godwit as well as other species. To learn more about the Important Bird Areas program and how you can help, visit: http://www.audubon.org/bird/iba/.
Information on where Marbled Godwits occur and in what numbers is vital to conserving the species. Help in monitoring this and other species by reporting your sightings to eBird. A project of Audubon and the Cornell Lab of Ornithology, eBird is the world's first comprehensive on-line bird monitoring program: http://www.audubon.org/bird/ebird/index.html.
U.S. National Wildlife Refuges provide essential habitat for Marbled Godwit, and a great number of other species throughout the U.S. and its territories. Unfortunately, the refuge system is often under-funded during the U.S. government's budgeting process. To learn more about how you can help gain much needed funding for U.S. National Wildlife Refuges, visit: http://www.audubon.org/campaign/refuge_report/
Volunteers are crucial to the success of programs that monitor the long-term status of wintering populations of Marbled Godwit and other bird species. Audubon's Christmas Bird Count (CBC) is one of the longest-running citizen-science monitoring programs in the world and has helped to follow changes in the numbers and distribution of Marbled Godwit. To learn more about the CBC and how you can participate, visit: http://www.audubon.org/bird/cbc.References
Brown, S., C. Hickey, B. Harrington, and R. Gill, eds. 2001. The U.S. Shorebird Conservation Plan, 2nd ed. Manomet Center for Conservation Sciences, Manomet, MA.
Gratto-Trevor, C. L. 2000. Marbled Godwit (Limosa fedoa). In The Birds of North America, No. 492 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Hayman, P., J. Marchant, and T. Prater. 1986. Shorebirds, An Identification Guide. Houghton Mifflin
Company, Boston.
Kaufman, Kenn. 1996. Lives of North American Birds. Houghton Mifflin Company, New York.
