The Gulf Coast marshes and rice fields provide substantial habitat for wintering white-fronted and snow geese. The GCJV midwinter goal for snow geese is approximately 1 million birds. Current numbers of snow geese wintering in the region likely exceed the goal in most years due to the burgeoning mid-continent population of these geese. Consequently, action should be taken to reduce the number of geese over-wintering in the region.
Overall, the Gulf Coast marshes are most important to North American waterfowl as migration and winter habitat. However, they are of critical importance to resident mottled ducks, with secondary importance to fulvous and black-bellied whistling ducks as breeding habitat. Limiting factors for breeding ducks are poorly understood, but availability of fresh water during spring and summer may limit availability of brood-rearing and molting habitat in some years. The primary limiting factor for populations of migrating and wintering waterfowl is assumed to be foraging habitat. The role of refuges and the need for additional refuges are not well understood in the region, and disease is generally not a factor.
Importance to other wildlife
The extensive wetlands of the Gulf Coast region provide habitat to large numbers of wading birds and shorebirds. Among these are the great blue, little blue, and green heron, great and snowy egret, and the white-faced ibis. Less common, but still occurring in considerable numbers are resident roseate spoonbills and migrant wood storks. Importantly, the marshes in the general vicinity of Aransas NWR along the Texas Mid-Coast provide winter habitat for nearly the entire population of the endangered whooping crane. Marshes, wet pasture and agricultural fields along the Texas Mid-Coast and Lower Texas coast also provide habitat for approximately 30,000 mid-continent sandhill cranes (Tacha et al. 1994).
The mid-winter inventory data for the Gulf Coast suggest an average population of approximately 800,000 coots. Population estimates for common moorhens and purple gallinules are lacking, but Gulf Coast marshes are very important for these two species. Further, this region provides significant habitat for wintering king, Virginia, and sora rails, and year-round habitat for resident clapper rails, though population indexes do not exist for these species.