Many of us will be heading to the ocean at some point during the summer. We may have relatives out on Cape Cod, a special affinity for a little shop in Rockport or we may just hear the siren song of waves crashing on the beach and are unable to resist its call. Regardless of our motivation, arriving at the ocean has a very special feeling attached to it. (I’ll have to think about how to put this feeling into word sometime, but that’s for another time.)
Once we arrive we are confronted with all manner of “new” birds that are at home in this dynamic environment and one of my absolute favorites is the great black-backed gull (Larusmarinus). The largest of our gulls, the “black back” (as I casually refer to it among friends) is surprisingly large. With a body length of 30 inches and a wingspan of 5½ feet, the gull is substantially larger than a red-tailed hawk (body length 19, wingspan 2 feet). In fact, the black back is more similar in size to a turkey vulture.
Found along the coast of New England throughout the year, the great black-backed gull goes through one of the most subtle changes in appearance to signify its breeding status. At about 4-5 years of age, the tissue around the bird’s eyes (called an orbital ring) will turn bright red. Birds will start a courtship of rather endearing qualities. The male will strut about and then bend his head downward and utter what has been described as a “mewing” call. He may also fly in large, lazy circles with slow wingbeats in the hopes of being joined by his mate.
Once mated, great black-backed gulls are monogamous. They will return to the same breeding area year after year in the hopes of rekindling their union with their mates. The oldest black back on record lived to be at least 26 years old (based on banding and sighting records) so there is a good chance that long, meaningful relationships can form between these birds.
A mated couple will work together in an effort to build the perfect home. They will cooperate in the construction of several different nests with the ideal location being near some sort of rock, bush or other large object that could provide some relief from the wind. The building materials will consist of plants and seaweeds and whatever flotsam and jetsam can be found in the area. The female signifies her final approval of a nest by laying her eggs in it.
A full clutch of eggs may only number two or three and the committed couple will share the responsibility of incubating their eggs for the month they require to hatch. Black backs nest among other gulls in colonies and their new chicks are small and vulnerable like any other baby birds that are literally surrounded by potential predators. To survive this danger, their chicks are able to get up and walk around after a few days; moving about the area to keep themselves safe, but not wandering so far that their parents can’t find them with food deliveries.
Great black-backed gulls are the largest gulls in the world and the chicks must grow for quite a while before they can fly (typically six weeks or so). Once they are fully mobile they must head out into the world and learn to be a gull for four or five years before they themselves think about breeding. Long before that, however, the young birds are able to inflict their will upon almost any other bird they encounter. An adult herring gull has little chance against an aggressive juvenile black back. This is surely the reason that the great black-back gull has been described as the “king of gulls.”
So, if you are lucky enough to find yourself at some special place on the coast I would highly recommend that you keep your eyes open for a great black-backed gull. After all, how often can you say that you were in the presence of royalty?
Bill Danielson has been a professional writer and nature photographer for 22 years. He has worked for the National Park Service, the US Forest Service and the Massachusetts State Parks and currently teaches high school biology and physics. Visit www.speakingofnature.com for more information, or go to Speaking of Nature on Facebook.