Ranger's Corner - March 2013
by Cristy Leonard
Skimmers on the beach at Anastasia State Park
Photo: Cristy Leonard
When feeding, this coastal water bird flies low, its long lower mandible slicing the water's surface in search of fish.
Photo: Dan Pancamo
Black Skimmers are the only birds whose lower mandible is longer than the upper. While resting, they sometimes lounge around, head and all!
Photo: Cristy Leonard
The Black Skimmer is distinctive for its unusual voice, brightly colored bill, and "skimming" behavior. When feeding, this coastal waterbird flies low, its long lower mandible slicing the water's surface in search of fish. Black Skimmers are the only birds whose lower mandible is longer than the upper. Black Skimmers are colonial seabirds that nest in groups, often with other species such as Laughing Gulls and Common, Least, or Gull-billed Terns. At hatching, the two mandibles of a young Black Skimmer are equal in length, but by fledging at four weeks, the lower mandible is already nearly 1 cm longer than the upper. Look for colonies on beaches, gravel or shell bars, dredge deposition islands, saltmarshes, and rooftops.
The Black Skimmer has one of the most unusual foraging styles of any North American bird. A feeding skimmer flies low over the water with its bill open and its lower mandible slicing the surface. When the mandible touches a fish, the upper bill (maxilla) snaps down instantly to catch it. Skimmers are highly social birds, nesting in colonies and forming large flocks outside the breeding season. Large, successful colonies usually occupy the same site from year to year, while small or failed colonies usually relocate.
Black Skimmers are not federally protected, but they are on several state lists, ranging from endangered in New Jersey to special concern in North Carolina and Florida. The main threat to skimmers in modern times is development or other loss of their beach-nesting habitat, since they nest on same the kinds of beaches on which people like to vacation. In addition to habitat loss, skimmer nests can be destroyed by roaming dogs and by vehicles that are allowed to drive on beaches. In the nineteenth century, a major cause of Black Skimmer declines was from hunting and the collecting of eggs. Egging used to be a commercial activity, and people reported colony sizes in terms of the number of bushels of eggs they would produce. Skimmers feed on small fish up to about 5 inches in length, including herring, killifish, mullet, and pipefish. They may also consume small crustaceans. Black Skimmers may travel 5 miles from their breeding colony in search of food.
The Black Skimmer is the only American representative of the skimmer family. The other two rather similar species are the African Skimmer and the Indian Skimmer. All use the same unusual feeding method.