Wildlife - Waterfowl Project Report

April 2005

Mid-Winter Surveys

Surveys of waterfowl are conducted across the continent for specific population management purposes at various periods each year. Survey efforts provide estimated numbers of waterfowl for year-to-year trend analysis. These include a mid-winter survey (MWS) tabulation of waterfowl by species conducted by cooperating Federal, state, and private personnel from ground, by watercraft and aircraft on and over traditional wintering habitats. These surveys do not provide an estimate of the numbers of waterfowl wintering in any state or survey unit during a given year or at a prescribed point in time. Further these surveys are subject to various errors which cooperating personnel strive to minimize in order to sustain validity of survey data for comparative purposes. Tables I and II provide MWS survey data for the past 2 years compared to the 5-year trend in SC and the 10-year trend in the AF. Figures 1-4 provide results and historical trend analysis of MWS efforts in SC and AF for ducks and geese from 1964-2005.

SC MWS dabbling duck numbers increased (+59.2%) in 2004 from 2003 and were substantially higher (+62.7%) than the average during 1999-2003. In 2005 dabbler numbers decreased (-24.7%) from 2004, but remained 11.4% above the average during 2000-2004. Green-winged teal and Northern pintail numbers demonstrated the most dramatic improvement with green-winged teal numbers climbing 90.5% in 2004 from 2003, dropping 16.8% in 2005, but remaining 52.4% above the average during 2000-04. Northern pintail MWS numbers were 71.6% and 38.4% above the averages of the 5-year periods preceding 2004 and 2005 respectively. Improvement in wintering Northern pintail numbers may be related to recent pro-active season length and bag limit restrictions benefiting this species. MWS diving duck numbers fluctuate from year-to-year due to weather, habitat related distribution, visibility, survey conditions and other factors. Diving ducks numbers revealed by MWS increased (+14.4%) in 2004 and decreased (-24.8%) in 2005 from preceding years. MWS goose numbers in SC remain low but demonstrated overall improvement increasing 12.7% in 2004 and 4.4% in 2005 as compared to the respective averages of the preceding 5-year periods; increases in snow goose numbers in both years accounted for increases.

AF MWS dabbling duck numbers increased 11.9% in 2004 from 2003 but were slightly below (-1.9%) the 10-year average from 1994-03. Dabbler numbers decreased (-22.9%) in 2005 from 2004 and were 25.2% below the 10-year average during 1995-04. AF diving duck numbers increased (+22.7%) in 2004 and decreased (-14.5%) during 2005 from preceding years, but in both years decreased (-18.3% and -36.8%) from the respective averages of the 10-year preceding periods. MWS goose numbers in the AF during 2004 were 18.9% above the long-term average but declined (-0.1%) in 2005 from average goose estimates during 1995-04.