Observation by Chief Chaaiy Albert, with help from Lars Flora:
We have observed parasites in black duck, also know as surf scoder. This while cleaning duck and parasites in breast meat during spring harvesting. We have noticed that in the spring with the ducks coming north on migration, the breast meat contains some kind of worm. In the fall as the birds are migrating south, the hunting is better because the birds have no parasites. We think the summer in the north helps return some birds to health.
LEO Network Says:
This is the first observation in LEO Network talking about season differences in migratory bird parasite loads. It is also the first post about parasites generally in surf scoters. During the June 2025 'Voices of the Land' meeting in Whitehorse, co-hosted by the Aleut International Association and the Arctic Athabascan Council, we heard similiar accounts from Tribal representatives in the Yukon Territory and in Alaska about parasites in waterfowl breast meat. Also the adoption of similar practices, a shift away from spring hunting and instead to fall because the fall birds have less parasites. This included reports from Chief Albert of Northway Alaska and Fort Smith elder Francoise Pauletter who spoke about the topic in a video intervew made by Arctic Athabascan Council Chief, Bill Erasmus. We have shared this post with our colleagues at the US Geological Survey, and the Alaska Department of Fish and Game. See also the 2012 LEO Network post from Victoria Kotongan in Unalakleet, describing worms in breast meat of grouse and ptarmagain she harvested. This observation was determined to be the furthest north and west identification of a worm*Splendidofilaria pectoralis* in grouse and ptarmigan. In this case, samples of the birds were sent to UAF and then Colorado State University for identification. In the case of the surf scoters, photos would be helpful to assist with identification. See comments below.
Comment from Andy Ramey:
The most common parasitic infection of duck breast muscle of which I am aware is sarcocystis, though it is impossible to confirm or rule out this possibility without photos, samples, or a more thorough description of what was observed.
Comment from Kimberlee Beckmen:
You can ask the National Wildlife Health Center. They are the waterfowl parasite/disease experts.
National Wildlife Health Center NWHC-epi@usgs.gov.
Comment by Barb Bodenstein, NWHC:
What you describe sounds like Sarcocystis species of protozoan parasites, also known by waterfowl hunters as "rice breast" but can’t be confirmed without photos or carcasses to examine and confirm through parasite identification. The most common species of the parasite in North America is Sarcocystis rileyi, and most common in dabbling ducks (mallard, northern pintail, northern shoveler, teal, American black duck, gadwall, and American wigeon). Infected birds can be found year-round, but usually observed during the hunting season. See NWHC field manual chapter 28 on Sarcocystis in wild waterfowl. Please do not hesitate to reach out with further questions. National Wildlife Health Center NWHC-epi@usgs.gov.