The Marbled Godwit is a large shorebird that breeds in the prairie regions of central North America and winters along the coasts of North America. Understanding where Marbled Godwits breed is important for conserving this species.
Breeding Range
Marbled Godwits breed primarily in the prairie regions of the central United States and south-central Canada. Their breeding range extends from central Alberta through Saskatchewan and Manitoba, south to Montana, North and South Dakota, Minnesota, Nebraska, and into northwest Iowa. Small numbers also breed in the interior of British Columbia.
Within this broad region, Marbled Godwits are found breeding in native grasslands, wet meadows, wetlands, and along rivers and streams. They prefer areas with short grasses and sedges interspersed with shallow wetlands or ponds. Marbled Godwits are sensitive to habitat alteration and tend to avoid agricultural lands and urban areas.
Key Breeding Areas
Some of the key breeding areas for Marbled Godwits include:
- Grasslands of southern Alberta
- Aspen Parklands of Manitoba
- Prairie Pothole Region of the Dakotas and Minnesota
- Sandhills region of Nebraska
In Canada, population surveys have shown that 50-80% of the continental Marbled Godwit population breeds in southern Alberta and southwest Saskatchewan. The Aspen Parklands region of Manitoba supports locally abundant breeding populations.
In the United States, the highest breeding densities occur in North and South Dakota, particularly in the Prairie Pothole Region where abundant wetlands provide ideal habitat. The Sandhills region of north-central Nebraska also supports a significant breeding population thanks to its native grasslands and wet meadows.
Habitat Preferences
Marbled Godwits show distinct habitat preferences when selecting breeding sites. Studies have found the following characteristics are important:
- Short grasses under 30 cm tall
- Low forb density
- Intermittent wetlands and ponds
- Gently rolling topography
- Lack of woody vegetation
Marbled Godwits avoid breeding in croplands, densely vegetated areas, and habitats disturbed by grazing or haying during the nesting season. Access to wetlands, even ephemeral ponds, provides important foraging habitat. In general, Marbled Godwits prefer large grassland landscapes over small fragments.
Nesting
Marbled Godwits nest on the ground in scrapes concealed by vegetation. Nests are typically lined with grasses, leaves, lichens, and feathers. Nesting occurs from late April through June, with peak activity in May. Clutch size is usually 4 eggs.
Both the male and female Marbled Godwit incubate the eggs for 21-25 days until hatching. The precocial chicks are able to leave the nest within a day and are brooded and protected by the parents. Chicks fledge at around 35 days old.
Threats to Breeding Habitat
The availability of high quality breeding habitat limits the Marbled Godwit population. Threats to their native prairie breeding grounds include:
- Conversion of grasslands to cropland
- Fragmentation from roads, oil wells, power lines
- Draining or modification of wetlands
- Tree encroachment in grasslands
- Livestock grazing that reduces nesting cover
Since the 1980s, North American grasslands have faced rapid losses and fragmentation. Estimates indicate only 30% of the northern mixed grass prairie remains intact. This habitat loss on the breeding grounds is the main conservation concern for Marbled Godwits.
Population Trends
North American Breeding Bird Survey (BBS) data from 1966-2015 shows a 1.11% annual population decline for Marbled Godwits during that period. However, trends vary by region:
Region | Population Trend 1966-2015 |
---|---|
Overall | -1.11% per year |
Alberta | +0.68% per year |
Saskatchewan | -2.06% per year |
Manitoba | -0.80% per year |
Montana | -2.39% per year |
North Dakota | -3.10% per year |
South Dakota | -2.30% per year |
Minnesota | -0.62% per year |
These BBS data show the strongest population declines in the U.S. states, while the trend in Alberta is slightly positive. However, the Alberta BBS routes may not sample some of the province’s key Marbled Godwit habitat. Overall, BBS data indicates a concerning declining population trend that is likely linked to breeding habitat loss.
Conservation Efforts
Several initiatives aim to protect and restore Marbled Godwit breeding habitat across the Canadian prairies and northern Great Plains region of the U.S. These include:
- Prairie Pothole Joint Venture – partners conserving wetland and grassland habitat
- Native Prairie Restoration projects
- Land trusts and conservation easements to protect private ranch lands
- Delaying haying of grasslands until after peak nesting season
More action is needed to conserve large tracts of intact native prairie to stabilize Marbled Godwit populations. Models suggest preserving complexes greater than 1,000 hectares would benefit Marbled Godwits the most.
Conclusion
In summary, Marbled Godwits breed primarily in the native grasslands and wet meadows of the northern Great Plains and southern Canadian prairies. Population trends show concerning declines that can be linked to extensive habitat loss and fragmentation on the breeding grounds. Ongoing conservation initiatives aim to protect and restore remaining tracts of native prairie to support Marbled Godwits and other imperiled grassland bird species. Maintaining large, interconnected regions of suitable breeding habitat will be key to sustaining Marbled Godwit populations into the future.