Movements and seasonal use of habitats by rural and urban female mottled ducks in southeast Florida

Abstract

ABSTRACTFlorida will continue to undergo high rates of habitat loss, primarily the result of urbanization. In addition, invasive species are a major threat to Florida's biodiversity. The Florida mottled duck (Anas fulvigula), a bird unique to the state, is particularly vulnerable to loss of wetland habitats and hybridization with feral mallards. Because mottled ducks are more likely to encounter feral mallards in urban habitats, we trapped and radiomarked adult females in urban (n = 99) and rural (n = 146) habitats to estimate home ranges and rates of movement into and out of urban areas. We also determined habitat use in urban and rural areas during the breeding (1 Feb–31 Jul), post‐breeding (1 Aug–18 Nov), and hunting (19 Nov–31 Jan) periods and estimated seasonal habitat selection of rural female mottled ducks. Urban females used mostly aquatic habitats in low and high intensity human development year‐round. Rural ducks used freshwater marshes throughout the year, but selection of other habitat types varied seasonally. Use of glades marsh and agricultural habitats by rural ducks peaked during the breeding season. Rural ducks selected artificial impoundments and reservoirs during the post‐breeding and hunting periods. Median home range size of rural females was more than 65 times greater than those of urban females. Our results suggest the spread of mallard genetic introgression caused by females leaving urban areas may be slow because as few as 6% of the adult females moved between urban and rural areas. Focusing wetland conservation efforts on freshwater marshes and artificial impoundments in south Florida would likely benefit mottled ducks. © 2014 The Wildlife Society.