Habitat and Population Evaluation Team
Midwest Region

Strategic Management Tools and Mapping Products:

 Expert Model for Marbled Godwit Landscapes (v. 2)

 map of marbled godwit distribution

Marbled Godwit Expert Model

Marbled godwits are large, high profile shorebirds that breed in the northern grasslands of the U.S. and southern Canada.  Like other grassland birds, godwit populations are in decline.  They are one of the few species of shorebirds that still breed in the tall grass prairie portion of the Prairie Pothole Region.  For many species, the landscapes suitable for breeding can be determined from existing datasets such as the Breeding Bird Survey.  Other species, such as the marbled godwit, are rarely detected on such surveys, making it more difficult to determine suitable landscapes based on existing empirical data.  Although there are many untested assumptions about factors that affect habitat suitability for godwits, the highest quality habitats are thought to be relatively large blocks of grass that include shallow wetlands, in low relief grass-dominated landscapes with few trees.  Marbled godwits are thought be a suitable “umbrella” species for other area sensitive grassland birds with many similar habitat needs.  The Marbled Godwit digital database depicts predictions about existing habitat suitability and restoration potential for this species.  It is based on a heuristic model and reflects the expert thinking of biologists from the Minnesota Department of Natural Resources and the US Fish and Wildlife Service who are knowledgeable about godwit habitat relationships.

Click here to view Marbled Godwit Expert Model

Model parameters include:

1) Patch size – >=320 acres (130 ha) minimum
     a)  >= ¼ mile wide (400 m) - okay
     b)  >= ½ mile wide (800 m) - better

2) Percent grass in landscape – 2-mile radius (3.2 km)
     a) 10-30% - okay
     b) >30% - better

3) Topography – Average percent slope was calculated for a circular 90 ha. area. Areas with an average slope of < 4% were considered good. Areas with an average slope >= 4% were considered less than ideal.

4) Trees – patch must be >100 m (328 ft) from trees

5) Wetlands - >= 4 acres (1.6 ha) of temporary and saturated wetlands within 320 acre patch.

bar-tailed godwit

For additional information on the marbled godwit model contact:

Diane Granfors, PhD
Habitat and Population Evaluation Team
US Fish and Wildlife Service
18965 County Hwy. 82 S
Fergus Falls, Minnesota USA

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Last updated: March 4, 2009