Habitat and Population Evaluation Team
Midwest Region

Predicted Duck Pair Accessibility Maps (Thunderstorm Maps)

          Breeding Pair Accessibility Maps are produced from long-term 4 square mile survey data. They are commonly known as “Thunderstorm Maps” because of a perceived resemblance to a Doppler radar image of a thunderstorm. Thunderstorm maps display predictions of the number of upland nesting duck pairs (mallards, blue-winged teal, gadwall, northern pintail, and northern shoveler) that could potentially nest in the upland habitats of every 40 acre block of the Prairie Pothole Region (PPR) of Minnesota and Iowa. These predictions are based on the known maximum travel distances of hens from wetlands to their nest sites, and regressions (statistical models) created from 4 square mile survey data predicting the number of duck pairs that utilize every individual wetland in PPR during a “typical” breeding season.
          The four square mile waterfowl survey is conducted annually and the wetland and waterfowl pair information collected from this survey is compiled periodically and the ability to re-evaluate the wetland and duck pair models is revisited. The models developed provide new updated predictions of waterfowl pair densities.  We are currently using the third generation of models that are based on over 20 years of data.
          Thunderstorm maps are used to help identify priority sites for the protection or restoration of grassland habitats for breeding waterfowl. They are also useful in identifying priority wetland complexes to be protected through acquisition of Waterfowl Production Areas and wetland and habitat easements, and areas to be enhanced by private lands wetland restorations.

View Thunderstorm Maps

1st Generation
“Tstorm Map”

2nd Generation
“Tstorm Map”

3rd Generation
“Tstorm Map”

District Thunderstorm Maps

For additional information about thunderstorm maps contact:
Dan Hertel
Wildlife Biologist
Habitat and Population Evaluation Team

Cry of the Marsh
Strategic Habitat Conservation
Last updated: December 9, 2009