CROW Case of the Week: Red-breasted Merganser (#19-1264)

The red-breasted merganser (Mergus serrator) is a long-bodied, diving duck with an impressive crown that involves a punk-style shaggy crest of feathers up top. It tends to swim with its head partially submerged to ready itself to dive after prey, which is usually small fish speared with its jagged bill. 

Red-breasted mergansers can reside in both freshwater and saltwater wetlands. They fly south to the southern portion of the United States or Mexico for the winter months. Interestingly, researchers say red-breasted mergansers require a daily intake of 15 to 20 fish for energy reasons. Studies reveal this would suggest nearly 300 underwater dives per day or a foraging period of four to five days. Not only are red-breasted mergansers great aquatic divers, they are regarded as among the fastest flying ducks and can clock speeds close to 81 miles per hour.

At CROW, a red-breasted merganser was admitted through one of CROW’s drop-off locations. No information was provided about where the bird had been rescued. The merganser was very quiet upon admission and had a two centimeter wide by four centimeter long laceration on its neck. The wound was severely contaminated. Veterinarians flushed the wound and cleared necrotic (dead) tissue from the edges of the wound before suturing it closed. They were unsure how the merganser was injured. 

“This duck might have been injured by a predator or by a fishing hook,” said Dr. Kyle Abbott, CROW Veterinary Intern. “The wound was contaminated with debris and had tissue changes consistent with being present for a few days. To treat this wound, the tissue was cleaned and then closed using sutures. The large amount of tissue missing on the neck meant that the rest of the neck skin would be tightened when the wound was closed. We had concerns for the patient’s ability to swallow initially, but this was not a problem for the duck.”

After two weeks in care, the patient was much brighter and faring better, however it has issues with its waterproofing which is vital for the success of this diving duck.

“Ducks and other birds use their feathers to form a waterproof barrier and keep them dry when in water. This process involves preening, where the birds align their feathers and apply oils to the feathers to form this barrier,” said Dr. Abbott. “We did have to perform a second surgery to revise the closure line. The reason for this was that the feather follicles were not aligning and the duck could not form a waterproof barrier despite appropriate preening behavior. The second surgery was to align these neck feathers better.”

More time will be needed after this second surgery prior to the patient being released. 

“It will take time before we know how the waterproofing is coming along, as there are still some feathers that need to regrow,” added Dr. Abbott. “Once we have the patient’s waterproofing appropriate to keep the duck dry when in the water, then release will be in a place where mergansers have been recently spotted at that time. We cannot release this duck exactly where it came from because we did not receive that information on intake.” 


CROW Case of the Week stories are written by Bob Petcher and appear weekly in the Island Sun and River Weekly Newspapers.

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