ANNAPOLIS — The Maryland Department of Natural Resources (DNR) 2006 Midwinter Waterfowl Survey counted 577,100 waterfowl this past winter, a decrease of about 32 percent compared to 889,900 tallied in 2005. Unseasonably mild weather contributed to waterfowl dispersement as inland ponds, reservoirs, shallow impoundments and the upper reaches of creeks and marshes remained ice-free. Thus, fewer birds were concentrated along the shorelines of the larger rivers and bays where aerial survey teams typically focus their effort.
The Midwinter Waterfowl Survey has been conducted annually throughout the United States since the early 1950s. The survey provides information on long-term trends in waterfowl populations. It is the only source of population estimates for species such as Atlantic brant and tundra swans. The survey provides critical information used in the management of American black ducks. The survey also provides supplementary information on other waterfowl species for which annual breeding population is available.
Survey teams representing the U.S. Fish and Wildlife Service and DNR’s Natural Resources Police Aviation Section and Wildlife and Heritage Service conducted this aerial survey Jan. 4-13. Airspace restrictions, especially along the Potomac and Patuxent Rivers and around military installations on the upper western shore, limited aerial coverage of the 2006 survey.
Total dabbling ducks in the 2006 survey were estimated at 50,300, a decrease from 82,800 in 2005. Mallards this year decreased to 32,500, down from the 52,800 counted in 2005. The largest concentrations of mallards were observed in the lower Chester River, downriver of Chestertown. Black ducks also showed a substantial decrease: 13,300 in 2006 versus 23,600 in 2005. The survey also showed lower numbers for American widgeon (300), and green-winged teal (400).
Divers in Chesapeake Bay were less abundant this winter. Total diving ducks in the 2006 survey were 140,200 compared to 300,600 last winter. The 2006 survey included 33,800 canvasback versus 39,400 last year and 79,400 scaup versus 189,800 in 2005. Large numbers of scaup were observed on the lower Chester River, Langford Creek, and the mouth of the Northeast River on the Eastern Shore. Bufflehead numbers were also lower: 11,800 compared to 22,000 in 2005. The total number of all ducks in the 2006 survey was 208,400, 52% lower than last year’s count of 433,200.
Canada geese this year numbered 305,400, 20 percent lower than the 383,400 geese observed in 2005. Mild weather contributed to Canada geese and other waterfowl being located inland from the Bay on freshwater ponds, unlike survey conditions in 2005 when ponds were frozen and geese were concentrated along rivers and Chesapeake Bay. Inland areas in Cecil, Kent, and Queen Anne’s Counties that contain substantial numbers of wintering geese are no longer surveyed. Because midwinter estimates reflect a mix of resident and migrant Canada goose stocks, these survey estimates are no longer used to guide hunting regulations. Regulations change in accord with the population status of Atlantic and Resident Populations of Canada geese, which are tracked using breeding population and productivity surveys conducted each spring.
Snow geese in the 2006 survey numbered 49,200, similar to the 2005 count of 54,900. A more reliable estimate of the greater snow goose population is made in May using aerial photography, when the entire population gathers on the St. Lawrence River estuary in southern Quebec before moving north to Arctic nesting areas. Another Arctic breeding species, the tundra swan, showed lower numbers in Maryland in 2006: 10,400 versus 13,200 in 2005. This decrease in swan numbers may be caused by tundra swans spending less time in the Bay and continuing southward to winter in North Carolina.