Habitat and Population Evaluation Team
Midwest Region


Waterfowl Breeding Pair and Production (4 Square Mile) Survey

Download the 2013 4 Square Mile Annual Report (8.5 MB PDF)

The annual Waterfowl Breeding Population and Production Estimates Survey was launched in 1987 as a means of assessing contributions of National Wildlife Refuge System lands in the Prairie Pothole Region to continental waterfowl populations. Originally developed by scientists at Northern Prairie Wildlife Research Center, the stratified random survey is conducted by USFWS personnel on 186 4-square mile sample plots in Minnesota, and by Department of Natural Resources employees on 60 plots in Iowa. Data are collected using ground counts in Minnesota and a helicopter in Iowa. In each 4-square mile plot, waterfowl and other wetland birds are counted on selected wetlands. Color infrared aerial photos of these plots are acquired annually to assess habitat condition.

Annual estimates of waterfowl abundance and production are generated from 4-square mile survey data, including statewide and wetland management district estimates of mallard, blue-winged teal, and total pairs; and of mallard, blue-winged teal, and total recruits. Recruitment estimates are based on wetland conditions at the time of the survey and upland habitat composition of the sample plots. Pair density and recruitment estimates also are provided by ownership stratum, including federal, easement, and private lands.

Each year the HAPET office distributes an annual report summarizing the results of the survey.

Publications relating to conducting waterfowl pair counts:
Assessing breeding populations of ducks by Alex Dzubin
Notes on conducting waterfowl breeding population surveys in the north central states
by M.C. Hammond
Classification of natural ponds and lakes in the glaciated prairie region by Robert Stewart and Harold Kantrud

For additional information about the 4 Square Mile Survey contact:

Fred Oslund
Biological Science Technician
Habitat and Population Evaluation Team


Cry of the Marsh
Strategic Habitat Conservation
Last updated: March 10, 2011