As the days get longer and the weather warms, most tundra swans are leaving Mattamuskeet NWR to return north. Many visitors this winter have observed dead or sickly swans along the banks of the Entrance Road impoundment. The unusually high mortality this year has concerned refuge staff and visitors alike. Two dead swans from the refuge were recently submitted to the National Wildlife Health Center for necropsy (autopsy for animals). Preliminary results are suggestive of lead poisoning, but we are waiting on toxicology results for confirmation. The birds were also tested for highly pathogenic avian influenza. Fortunately, those results were negative. Final results are pending, but lead poisoning has been confirmed in other birds submitted for testing from this location in previous years. Prior to the 1991 nationwide ban, lead shot was used extensively for waterfowl hunting. It is possible that the resulting lead shot in the environment is causing this unintended mortality in the swans today.
Swan Mortality at Mattamuskeet National Wildlife Refuge
