Status, Distribution, and Foods of Fulvous Whistling-Ducks in South Florida

Abstract

A breeding population of fulvous whistling-ducks (Dendrocygna bicolor) has become established in south Florida, representing an increase in Florida's resident waterfowl resource. This population is centered in the Everglades Agricultural Area (EAA), and is closely associated with rice culture, which provides nesting, brood-rearing, and feeding habitat. During fall and winter, ducks move to natural marshes throughout the southern half of the state; however, an unknown percentage migrate to Cuba. Fulvous whistling-ducks rely primarily on rice seeds when occupying EAA rice fields, and seeds of emergent aquatic plants are important foods in the spring. Development of an accurate census or index, and studies on the reproductive ecology of fulvous whistling-ducks in Florida are priority management needs. J. WILDL. MANAGE. 53(4):1046-1051 Fulvous whistling-ducks inhabit much of the Western Hemisphere, with 2 widely separated populations in South America, and populations in Mexico, Texas and Louisiana, California, and Florida in North America (Bellrose 1980). Fulvous whistling-ducks are a regular winter visitor to the Atlantic Coast of the United States, particularly Florida, since 1955-56 (Jones 1966). Bolen and Rylander (1983) speculated that winter visits may be a precursor to summer flights and breeding, similar to the pattern that established a breeding population in Louisiana. The first breeding record in Florida was reported June 1965 at Eagle Bay, Lake Okeechobee (Ogden and Stevenson 1965). Landers and Johnson (1976) postulated that the fulvous whistling-duck successful range expansion may have been indicative of adaptation to similar feeding habitats between old and new range sites, and emphasized the need to gather information on the natural history and behavior of this species. Bolen and Rylander (1983) noted the importance of rice culture to dispersal of fulvous whistling-ducks and expansion of their breeding range. Indeed, establishment of the Louisiana population has been attributed to development of rice culture (Lynch 1943). Rice culture has developed recently in south Florida, particularly in the EAA agricultural complex. Commercial rice production in the EAA began in 1977 (Rohrman and Alvarez 1984), and since 1979 approximately 3,500 ha have been planted annually (Rohrman and Alvarez 1984; Game and Fresh Water Fish Comm. [GFC] file data, Okeechobee, Fla.). There are no published articles on the life history, ecology or status of fulvous whistlingducks in Florida. There is a paucity of information on this species in North America, and few published studies are recent (e.g., Meanley and Meanley 1959). We report the current status, distribution, and diet of fulvous whistlingducks in Florida. Collection and banding assistance by F. Montalbano, III were instrumental to completion of this study. D. J. Forrester provided laboratory assistance, D. R. Eggeman assisted with data compilation and statistical analyses, and G. L. Warren identified invertebrates. We thank E. L. Flickinger and E. G. Bolen for their review of an earlier draft.