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Conducting Waterfowl Surveys

Assessing Wildlife and Their Habitat
mixed waterfowl 520x303

Waterfowl surveys offer an opportunity for refuge biologists to assess habitat usage, species presence and migration patterns throughout the migratory season. Depending where and how surveys are completed, various results can be obtained. 

Aerial surveys are accomplished from small aircraft at low altitudes. When doing aerial surveys, these low-level flights occur over all or identified sections of land that waterfowl are known to use. Counting methods and species identification are a skill acquired by biologist over time and with experience. These aerial surveyors do not count individual ducks throughout the flight as much as they do counting in groups. For example, groups of 10, 50, 100, etc.. Aerial surveys often provide more complete calculations of waterfowl over a given area. You can learn more about the history of aerial surveys here.

On the other hand, ground surveys, like those completed at Clarks River NWR, offer a glimpse of species currently present and identify the habitat they are using at the time of the survey. Ground surveys can be completed visually just with the surveyor’s eyes, or with ocular devices such as binoculars or spotting scopes. These surveys take place at areas identified as habitat with abundant waterfowl usage and where they can occur without flushing or disturbing the birds. In no way do ground surveys provide a total numbers of waterfowl utilizing the refuge. 

At Clarks River NWR, surveyors drive to each of our managed waterfowl impoundments. Then, from predetermined viewing locations, species are identified and counted as accurately as possible by using the grouping method as described above. Therefore, our surveys only provide species totals for the birds present in those areas and at those exact times. These surveys are conducted bi-weekly throughout the migration period.

One last thought on waterfowl surveys. Biologists are using a grouping method and counting by 10s or even 100s, but let's say the survey numbers reported there were 4,103 ducks counted. How in the world did they come up with the 3?! Well, it’s really not as far-fetched as it seems. Using the grouping method, it is very easy to count a number of approximately 4,100 ducks, but then off to the side of the pond or wetland a biologist may count 3 ducks. Incidents like this are what results in such apparent exactness within a waterfowl survey

Facts About Conducting Waterfowl Surveys

Experienced biologist that were trained as pilots during WWII, became an essential part of waterfowl surveys after the war when they returned home.  

Every year a team of U.S. Fish and Wildlife Service biologist fly over 80,000 miles across North America to help determine waterfowl populations.

The U.S. Fish and Wildlife Service's annual Waterfowl Breeding Population and Habitat Survey Report is produced from both aerial and ground surveys. It is this report that helps determine waterfowl hunting season dates, lengths, and bag limits. 


Page Photo Credits — Mixed Waterfowl - rstainfield/usfws
Last Updated: Oct 04, 2016
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