Use of flooded timber by waterfowl at the Montezuma National Wildlife Refuge

Waterfowl use of bottomland hardwood timber stands which were flooded and killed was studied at the Montezuma National Wildlife Refuge, Seneca Falls, New York, from 1962 to 1964. Comparisons of use were made among six habitat types containing dead timber, stumps, and no timber, and with and without emergent vegetation. An index to waterfowl use was derived by direct counts and by counts made with automatic cameras which photographed randomly selected plots in each habitat type. Movement between types was studied by observation of both marked and unmarked birds. The camera index of use showed that cut timber with emergent vegetation received the greatest overall use. Use was positively correlated with the proximity of the plot to emergent vegetation and nearest vegetative type boundary. A stand flooded for 7 years was used primarily by black ducks ( Anas rubripes) and mallardls ( A. platyrhynchos) . Use of stands flooded for 20 years was dominated by American widgeon (Mareca americana). Waterfowl spent more time resting than feeding in timbSered areas, and more time feeding than resting in marsh areas. Young-of-the-year did not move between pools after they had reached an age of IIc ( Gollop and Marshall 1954 ). Use by broods was greatest in areas near emergent vegetation. Flying birds used timbered areals during the daytime and non-timbered areas at night during fall. Flooded dead timber appeared to be attractive to waterfowl because it furnished abundant loafing sites. The management of green tree reservoirs for production of both waterfowl and wood has become a recognized practice in the south (Rudolph and Hunter 1964) but little is known about the value of dead timber impoundments in the north. The Montezuma National Wildlife Refuge contains several large tracts of bottomland timber which were flooded in the past as well as large areas of cattail ( Typha sp. ) marsh which are without timber. The presence of these areas furnished an opportunity to study a type of waterfowl habitat about which little was known. This paper describes the use of the flooded-timber habitats by waterfowl and compares it with that of cattail marsh habitats. An earlier paper ( Cowardin et al. 1967 ) described waterfowl production on the same areas. Uhler ( Personal communication ) studied 1This study was supported by the New York Cooperative Wildlife Research Unit and the Division of Wildlife Refuges of the Bureau of Sport Fisheries and Wildlife. 2 Present address: Northern Prairie Wildlife Research Center, Bureau of Sport Fisheries and Wildlife, Jamestown, North Dakota. waterfowl use and production on a number of small impoundments containing dead timber at the Patuxent Wildlife Research Center near Laurel, Maryland. He found that impoundments with dead timber soon became choked with bladderwort ( Utricularia sp.) and that value to waterfowl was limited. When dead timber was removed from the impoundments following drawdown, Uhler noted an increase in valuable waterfowl food plants and in waterfowl use. DiAngello ( 1953 ) studied plant succession, and waterfowl use and production on several flooded forest impoundments of varying age in Michigan. He found that the impoundments were of considerable value to waterfowl but that their value diminished with time. He attributed the loss in value to a decrease in the amount of duckweed (Lemna spp.) which was present in the first few years after flooding. Moore (1959) studied the vegetation and waterfowl use of a number of flooded swamps in eastern Massachusetts. He found that wood ducks (Aix sponsa) and black ducks made extensive use of wooded impoundments during fall mi-