Current Waterfowl Data: (2006-2007 Season)
Refuge waterfowl surveys have been conducted in two ways in the past - aerially and on the ground. During aerial surveys, a plane is flown at about 200-300 feet above the refuge in areas where waterfowl are typically found and the number of each species counted. Ground surveys are conducted along standard routes in typical use areas that can be accessed. Observers use spotting scopes and/or binoculars to count and identify birds along standard routes.
These counts are not counts of all of the waterfowl on the Refuge. It is essentially impossible to count every bird here. Surveys are intended to determine trends in waterfowl abundance. In other words, they determine whether waterfowl numbers are increasing, decreasing, or remaining the same over a number of years. To perform these counts properly, the same technique should be used during each survey. This includes conducting them on about the same dates, using the same routes, using the same observers to the extent possible, and other similarities. This also includes using the same techniques during either aerial or ground surveys. Surveys are currently conducted every two weeks from about mid-October to early March.
In the past few years, aerial surveys have been a challenge due to the difficulty of finding available finding pilots and airplanes that meet Department of Interior standards. Thus, we have had to rely more on ground counts. Most of the counts that have been conducted on Wheeler National Wildlife Refuge since 1947 have been by airplane.
When comparing counts over a number of years, information from the same time period must be compared. Counts in mid-October are typically much lower than in late December or early January. Thus, when comparing counts to determine trends, mid-October data of one year should be compared with mid-October data of previous years and early January data compared to early January data of previous years. Usually for determining trends, we use early January data because most high counts of birds in past years have occurred during this time period. Total numbers of waterfowl counted on the Refuge since 1947 are presented in three seperate files: