Population Surveys

Pintails flying

Population Surveys


Waterfowl Breeding Population and Habitat Survey

The Waterfowl Breeding Population and Habitat Survey (May Survey) is an aerial survey conducted in the U.S. and Canada and it provides annual breeding population estimates for most duck species in North America.

The May Survey also provides:

  • An assessment of breeding habitat conditions
  • Triggering levels for harvest regulations through Adaptive Harvest Management
  • Information to assess objectives within the North American Waterfowl Management Plan

The May Survey became operational in 1955 and the area covered by this long-standing survey is commonly referred to as the "traditional" area, which covers 1.3 million square miles in Canada, Alaska, North Dakota, South Dakota, and Montana. The Eastern Survey Area became fully operational in 1996 and covers and additional 0.7 million sq. mi in eastern Canada.


  • The May Survey is conducted by two highly trained biologists, one of which is also the pilot
  • Each observer is responsible for counting waterfowl and ponds on their respective sides of the plane
  • Flight altitude is generally between 100-150 feet and speeds are held between 90-105 mph
  • Each bird or pond observation is recorded directly into a computer file via a microphone and the corresponding location from the GPS is automatically recorded

Data collected along each established flight path or transect consists of:

  • The number of pairs, single ducks, and ducks in flocks for each species
  • The number of "ponds" or wetlands with water

These data allow the calculation of an annual index to the number of ducks for each species in the breeding population and are ultimately used by manager in the Central Flyway to monitor populations and determine hunting seasons.

More information regarding the May survey can be found by visiting the USFWS website.

Further information and results of the May Survey can be found in the Waterfowl Population Status Report.