The Preacher Gulls -- by Kenneth Turner Blackshaw

High above me, through the crystal clear air of a late winter day comes a marvelous sound that reminds me that spring is just around the corner. I look up into the stunning blue sky and see two black and white figures, stroking their way across the firmament, calling hauntingly back and forth. I've learned to listen for these deep "owk - owk" calls in late February and March on sunny still days when their calls penetrate the dry atmosphere from high above. This is the beginning of the pair bonding process for Great Black-backed Gulls.

With a wingspan as long as the average man is tall, this gull is the largest in the world. It is so huge that it is often confused with the Bald Eagle. Many people immediately think -- 'eagle' when they see a bird of this size. The fact that adult Black-backs have white heads and tails, sharply contrasting with the black on the back, adds to the confusion.

Although we now see Black-backs commonly year round, it wasn't always thus. They were only winter residents on Nantucket in the first half of the 20th century, and it caused excitement to find one here as early as September. Nowadays, its nesting range now extends down to Long Island -- global cooling instead of warming? Well, in this case, it's just another successful species being crowded out of its nesting grounds and forced to move south. This is in spite of the fact that until recently, up north, young gull chicks were still fattened up for the stew pot. On Nantucket, they nest at the island's extremities, now pushing out the Herring Gulls who in turn, have pushed out our terns.

When I was learning to bird here in the 50's, they were nicknamed, the 'preacher' gull. There would generally be just one or two, with each flock of Herring Gulls. Their black and white clerical garb made them stand out from the rest, like a minister with his flock. Times have changed and now the ministers often outnumber their parishioners.

Although they are here all year, the population shifts with the season. Our winter gulls spend the summer in Labrador and Newfoundland. These huge gulls range over the entire north Atlantic, across to northern Russia into the Mediterranean.

Identifying gulls is difficult for beginning birders because the young birds look so different. I once had a report of seven species of gulls along the Jetties Beach shore one winter morning. When I arrived there, I only found Herring Gulls and Black-backs. The problem is these are both 'four year' gulls. That is, they take four years to attain their adult plumage. Great Black-backed Gulls don't get their black backs until the fourth year. Before that, they are brown on the back and white below -- browner in the first years and then gradually becoming grayer. They present a more checkered appearance than the Herring Gulls with whom they associate. When sitting on the beach, their large size and bulk distinguish them from other gulls. Even the juvenile gulls are huge.

A similar species is the Lesser Black-backed Gull, which we see here every winter in small numbers. Lesser Black-backs are a European species which straggles to the east coast. It is a bit smaller than the Great Black-backed and has yellow legs, compared to the more common bird's flesh-colored ones. This does no good when they are swimming but is handy on the beach.

Black-backs eat almost anything. The writings comment, "The great black-backed gull is a voracious feeder, omnivorous, and not at all fastidious." Often we see an aerial dogfight as two or three gulls chase each other because of some goody the first one has snatched. On the nesting ground, they feast on the eggs of other gulls and their young. It's hard not to be critical of this type of behavior, but nature can be harsh.

Gull behavior is often a joy to watch. Certainly their flying ability makes us all envious, but they also know how to take a good bath. One bird bathing is enough to get the whole flock going at it. I watched a Black-back at Gibbs' Pond this week, flapping awkwardly, but joyously, spraying water hither and yon. Their antics are more tangled by the fact they are floating in the water rather than standing in it. Occasionally they roll over, wings akimbo. They also like to dunk their heads. This is all done very industriously, reminding me of my mother's advice -- "Cleanliness is next to Godliness". These 'preacher' gulls are definitely on their way to heaven.

So, if you are outside on one of our beautiful late winter days, listen for the mournful croaking sound from above that is the beginning of another nesting season for these beautiful gulls. Imagine what the world must look like from a few hundred feet up as they row through the air. It will be another month or more before they start working on their huge, grass and seaweed woven nests, but spring is definitely on the way.

George C. West creates illustrations for these articles.

If you enjoy social birding, every Sunday a group meets in the parking lot in front of the Nantucket High School at 8 a.m.

To hear about rare birds, or to leave a bird report call the Massachusetts Audubon hot line at 888-224-6444, option 4.