CROW Case of the Week: Double-Crested Cormorant (19-4220)

The doublecrested cormorant (Phalacrocorax auritus) is a large water bird with a long S-shaped neck and a prehistoric look. While it is related to the frigatebird, this swimming bird looks more like a cross between a goose and a loon, and sometimes is confused for the latter. The cormorant gets its name from its double crest that is only visible on adults during breeding season. The cormorant crests are black in most regions, except for Alaska where they are white.

The double crested cormorant is an accomplished diver and uses its hooked bill to catch small fish underwater. It can be seen in both freshwater and coastal waters.

When not plunging below the water surface, the most widespread cormorant in North America is often seen on a rock or other surface with its wings spread out. This drying stance is usually performed when the bird is taking a break from fishing. It must take the time to dry itself because it has less preen oil than other birds, and its feathers can get quite soaked from diving excursions. Unfortunately, it does not have the ability to shed water like a duck.

At CROW, a juvenile double-crested cormorant was admitted from a beach on Sanibel. The patient was unable to act normally or evade capture. Upon examination, the cormorant had clear struggles breathing and noticeable swelling of the head and neck area, which was said to be associated with a leaking of air in the body. To investigate the source, CROW medical staff performed an endoscopy procedure through the trachea to search for a possible tear causing the air leak. For the procedure, a small incision was made below the last rib to place a breathing tube directly in the air sac, allowing breathing during the tracheal procedure.

Roughly 10 days after the procedure, the patient is doing much better. “The swelling has gone down in the head and neck area. There still is a small amount of air swelling remaining, but the draining tubes under the skin appeared to work well to continuously drain the air out from underneath the skin,” said Dr. Megan Cabot, CROW veterinary intern. “The incision allowed us to place a breathing tube in the air sacs inside of the body, instead of through the trachea where we normally place a breathing tube for surgery. The air sac tube allowed breathing while we scoped the trachea. This incision was closed after the procedure because the bird’s trachea appeared unaffected.”

Since there was no tear in trachea, the source of the leak was believed to be coming from an air sac that is located at the base of his neck, according to Dr. Cabot.“We suspect this cormorant sustained an unknown trauma, as air sac ruptures are often caused by blunt force,” she said. CROW medical officials are optimistic but guarded moving forward with the patient.“Since the draining tubes were placed in the skin of the neck, air swelling has remained mostly resolved,” added Dr. Cabot. “Today (October 19), we pulled the tubes and will monitor over the next few days to make sure the cormorant does not swell up again with air.”

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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