For almost 40 years, the Division of Fish and Wildlife has conducted four waterfowl surveys annually to measure long-term trends in duck and goose populations. These surveys are carried out via a small plane with a pilot and biologist aboard, taking similar routes and using the same techniques each time. Flights are usually made in mid-October, mid-November, mid-December and the second week in January, subject to weather and mechanical delays. The January flight is part of a coast-wide effort to survey waterfowl throughout the Atlantic Flyway at approximately the same time. The state surveys cover the primary waterfowl habitat in Delaware, approximately the eastern half of the state, and are divided into 11 zones.
Not all ducks and geese can be seen equally well from a plane. The surveys give fairly accurate information about geese, but duck populations such wood ducks and sea ducks are almost impossible to count.
The important feature of these counts is that they augur for long-term trends that are useful to measure changes in waterfowl management strategies and the environment. In most cases no single survey count is especially important in itself, but cumulative counts have revealed important changes over the years. (Photo courtesy of Joey Melvin)
For example, the state's waterfowl surveys detected the decline in the migrant population of Canada geese, the dwindling use by ducks of the Christiana marshes after Interstate 95 was constructed, and recent increases in ducks using the Prime Hook National Wildlife Refuge area after the refuge accomplished phragmites and water control. Winter counts are used as a measure of black duck abundance and other population changes. Although imperfect, surveys are a useful tool for waterfowl manager.
Waterfowl counts are summarized within the following zones:
Zone 1 - (Width of the State) Pennsylvania Line to the Delaware Memorial Bridge.
Zone 2 - (Width of the State) Delaware Memorial Bridge to the C&D Canal.
Zone 3 - (Width of the State) C&D Canal to a Line from Liston Point to Kenton.
Zone 4 - (Width of the State) Liston Point to Route 6 (Smyrna).
Zone 5 - (Width of the State) Route 6 to Route 8 Port Mahon.
Zone 6 - (East of 113) Route 8 to Big Stone Beach.
Zone 7 - (East of Route 1) Big Stone Beach to Broadkill River.
Zone 8 - (East of Route 1) Broadkill River to Bend in Lewis Rehoboth Canal South of Gordon's Pond.
Zone 9 - South of Gordon's Pond and All of Rehoboth Bay.
Zone 10 - All Indian River Bay West to Millsboro and South to Salt Pond.
Zone 11 - Salt Pond South to Maryland Line and West to Route 17.
Historical Waterfowl Survey Data
Season Selection Index