Upper Mississippi River National Wildlife and Fish Refuge
August 3, 2022
Mortality events in migratory birds have been occurring throughout the Mississippi Flyway since the detection of bird flu in South Carolina in mid-January. Locally, small groups of ducks, geese and swans were subsequently found dead in Pool 13 of the Upper Mississippi River during the spring migration. This pool is an important stopover area for many migratory bird species including bald eagles and hawks that also were found dead. Currently, there is an extensive die-off of American white pelicans and double-crested cormorants.
Bird flu is scientifically referred to as highly pathogenic avian influenza (HPAI). This highly contagious virus is a major reservoir for influenza A viruses which can infect poultry, dogs, cats, pigs, fox and humans. Wild waterfowl seldom display clinical signs when infected making them a good source for virus transmission.
This virus infects the bird’s digestive system, in contrast to the respiratory infection in humans and other animals. This infection causes the virus to be passed in their feces, allowing for wide geographic transmission within waterfowl and to other species during migration. Bird flu has been confirmed in commercial/backyard poultry flocks and has killed millions of chickens and turkeys.
Four islands in lower Pool 13 contain nesting colonies of waterbirds that include American white pelicans, double-crested cormorants, great blue herons and great egrets. Colonial nesting birds are in close contact with each other and are at a much greater risk of getting bird flu. Pelicans are primarily being impacted with current estimates of 1,000+ dead. Hundreds of dead cormorants have also been observed. Pelican carcasses were sent to the National Wildlife Health Center that confirmed bird flu.
Human infections with the bird flu virus are typically rare, but can occur, usually after close contact with infected birds or virus contaminated environments. In April, the CDC confirmed the first case of the virus in a person involved in depopulating an infected poultry facility in Colorado. The most effective control to minimize exposure, is to keep humans and domestic animals away from healthy, sick, and dead wild birds.
The Upper Mississippi River National Wildlife and Fish Refuge is the most visited refuge in the United States. The refuge extends 261 miles along the Upper Mississippi River from Wabasha, Minn. to Rock Island, Ill., protecting and preserving habitat for migratory birds, fish, and a variety of other wildlife.
