Editor’s Note: The American Herring Gull is part of the CROW CAW (Case A Week) series, which tells the stories of the patients at the Clinic for the Rehabilitation of Wildlife on Sanibel Island, the dangers they face, and how we can help protect all of our wildlife. Read previous cases here.
At Lovers Key State Park, a beachgoer spotted an exhausted American herring gull (Larus smithsonianus) lying on the sand. Strangely, the gull’s feathers were bleached, broken, and crispy to the touch. Realizing the bird needed help, the finder brought it to the Clinic for the Rehabilitation of Wildlife (CROW) for treatment.
Birds can develop abnormal feathers for many reasons, including malnutrition, chronic illness, and environmental damage. Although the exact cause of the gull’s abnormal feather condition remains uncertain, the bird was severely emaciated, and its bloodwork showed signs of significant inflammation. This suggests that the gull was dealing with an underlying disease that may have contributed to its poor condition.
CROW’s staff treated the bird with antibiotics and antifungal medication. The animal responded to treatment, and bloodwork normalized.
However, the extensively damaged feathers cannot simply be repaired. Gulls generally complete a feather molt once per year, during which old feathers are replaced by new ones. In the wild, this allows birds to withstand damage from normal wear and tear, parasites, UV rays, and other factors.
For birds with only a few damaged flight feathers, CROW’s staff may use feather imping, an ancient falconry technique that attaches a donor feather to the remaining shaft of a broken feather.
However, this gull has too many damaged feathers for imping. The bird will need to undergo a natural molt to replace the abnormal plumage.
CROW’s staff have moved the bird to a spacious outdoor rehabilitation enclosure complete with a shallow pool. This allows the gull to recover and regain strength while waiting for the feather molt.
American herring gulls are one of the many gull species found in North America. Often, these birds are lumped together as “seagulls,” but each species has a distinct appearance, behavior, and natural history.
American herring gulls are opportunistic omnivores, meaning they’ll eat just about anything. This can include crabs, oysters, eggs, fish, and even trash, which can sometimes lead to injury or illness.
American herring gull populations declined by 82% between 1966 and 2021, according to the North American Breeding Bird Survey.