In last week’s column I mentioned that Bruce Horwith found a dozen dead loons on the Napeague ocean beach. Peg Hart of the Seabird Ecological Assessment Network (SEANET) was interested in examining the birds, so last Monday afternoon Bruce and I met at Indian Wells beach to collect them.
All 12 were red-throated Loons (
), and many of them seemed to be only hours dead. Two were found with fish protruding from their bills, and one of the meals was clearly identifiable as a silverside (
) species. We also found a half-dozen small sharks (3-to-4-feet in length) on the beach. My guess is that these were smooth dogfish (
Mustelus canis canis
). While taking close-up photographs, I realized that these bottom foragers, whose main prey includes most of our marine crabs, squid, lobster and moon snails, were still alive. Their presence on the beach may be related to the cause of the loons’ deaths.
Monday’s loons, approximately 36 pounds of them, were taken to the East Hampton Town office of natural resources director Larry Penny to be stored in a large freezer. On Wednesday, I resurveyed the Napeague beach and picked up another 14 red-throated loons and two common loons. Later I learned that SEANET volunteer Job Potter retrieved another 10 from the ocean beaches of west Amagansett, bringing the total number of recent loon mortalities to nearly 40. All were carted off to the American Museum of Natural History on Friday, after a final search revealed no new loons.
In North America, red-throated loons have a more restricted breeding range than common loons, building their ground nests on the edges of ponds and lakes in the tundra, or on open coastal flats bordering the boreal forest. The closest nesting areas to Long Island are Newfoundland and the James Bay coast of Quebec and Ontario. Red-throated loons also nest in similar habitats found in northern Europe and Asia.
Common loons also nest in the far north, but their breeding range extends south to the Great Lakes, the Adirondacks, and New England. In the spring of 1982, I monitored the southernmost nest site in the northeast, located on Willard Pond in Hancock, New Hampshire. That pair constructed their nest on a raft of cedar logs that we had anchored in 4 feet of water not far from the pond shoreline. The floating raft ensured that the nest would not be flooded, or left too high and dry for the adults to exchange places during incubation, as the pond’s water level fluctuated. Today, the southernmost nesting site is further south, located in central Massachusetts.
Both species winter along the eastern seaboard: the red-throated as far south as Georgia and the common loon into the Gulf of Mexico. Here on eastern Long Island, winter bird counts often tally hundreds of loons, and it is not unusual for the red-throateds to outnumber the commons. Several birders estimated 200 to 300 red-throated loons off Montauk Point last week, probably chasing the same baitfish that sent large schools of bluefish and striped bass around the point and along the ocean beaches.
Peg Hart’s preliminary work on the loons seems to indicate that the cause of death was drowning, based on the condition of the lungs examined. How does a healthy aquatic seabird drown? These birds may have been inadvertently caught in gill nets set just off our ocean beaches. Tissue samples still need to be analyzed for toxic substances, and those results will be included in a report to be submitted to federal and state officials for review and discussion.
Mike Bottini is a naturalist and author of “The Southampton Press Trail Guide to the South Fork” and “Exploring East End Waters: A Natural History and Paddling Guide.” Check www.peconic.org for Mike’s field naturalist classes.