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48 STATE OF THE ESTUARY 2015 In general, breeding waterfowl numbers are higher in areas with more available habitat, appropriate land use practices, and lower threats from predators like foxes and falcons. Higher rainfall years also tend to support more waterfowl than dry or drought years. INDICATOR This breeding waterfowl in- Pintail pair in flight (and green-headed male mallard in the water). Photo: USFWS BREEDING WATERFOWL CONTEXT Most locals know the differ- ence between a web-footed duck and a long- legged shorebird; many can even name the more common green-headed mallard male on sight. Few may know that the mallard is a dab- bling duck, a duck that feeds on the surface with tail tipped in the air, and that dabblers are among the most abundant breeding water- fowl in the Estuary. As such, the abundance of five common dabblers offers a strong indicator of the health of the region’s native wildlife. Breeding ducks need undisturbed uplands for nesting in proximity to water. During the month while they lay and care for their eggs, they forage in adjacent waters for food. Shortly after their eggs hatch, they bring their brood to the water. Such habitats are not always pristine. In the Delta, ducks share habitats with farmers; in Suisun Marsh, their habitats are hunting clubs, some of which are also managed to support breeding waterfowl. Fall and winter hunting is a popular pastime in many of the region’s more rural areas, and healthy waterfowl breeding populations are important to hunters and bird- watchers alike. Higher breeding populations in California can mean higher hunting bag limits set for the state. dicator measures annual abundance of five of the most abundant dabbling duck species in the Estuary: mallard, gadwall, green- winged teal, Northern pintail, and Northern shoveler. The indicator combines data on abundance from two separate regions of the Estuary — the Delta and Suisun Marsh — between 2010 and 2014. Data was sourced from California Waterfowl Breeding Popula- tion Survey 1992-2014 and also compared to statewide trends. Benchmarks derive from mean abundance between 1992 and 2001, the first ten years of the survey. Less than 60% of benchmark was considered poor condition in this analysis. STATUS & TRENDS The current status for the five most abundant species of breeding waterfowl in the Delta and Suisun Marsh is fair but decreasing from baseline. The trends are different for mallards relative to the remaining four species, particularly in the Delta. Mallards are the dominant waterfowl species in the Delta (~92%) and Suisun (~59%). Since 1992, mallard abun- dance decreased more than 2% per year in both regions. For the remaining four waterfowl species, abundance is increasing at a rate of 7.7 percent per year in the Delta