The Great Northern Diver
By Kenneth Turner Blackshaw
A loud, maniacal call permeates the air, jarring me from my sleep. It's about 6 a.m. and seems dark to me although the sun is on the horizon. I wait for a second, thinking it's part of a dream, and then it comes again -- a quavering, whistled note. Yes, it is a Common Loon, the sound diminishing rapidly as the bird wings off. It must have been flying along, not far above our house in the twilight, calling as it went.
The call of the loon is such a heart wrenching sound. I remember hearing them in the movie "On Golden Pond". The loons seemed to represent all the tradition the family had, living on that isolated lake. Loons are favorites amongst humans. The Canadian dollar has a loon on it and is referred to as a "loonie". The Common Loon is also the state bird of Minnesota.
So what is a loon and why do we care about them? Common Loons are large, duck-like birds that swim and dive in the water. In Eurasia, they are called Great Northern Divers and the Latin species name 'Gavia immer' means diver as well. The word 'loon' actually comes from an Icelandic word referring to their awkward gait on land. The similar word 'loon', referring to a simpleton, also applies because this bird's maniacal laughter sounds like the laugh of a crazy person. Then of course there is the loony connection with people acting strangely during the lunar full moon.
But, crazy or not, diving is what these birds do and that's what my first memories are. I would stand at the end of Steamboat Wharf on a cold winter morning and watch loons. They would dive and seem like they would never come up. I mean, you wait and wait, and look and look. Thirty-five or forty seconds can seem like an eternity. Sometimes you would see the bird pop up, other times it would have traveled so far it would be out of sight. So they seemed like marvelous diving machines and I'd wonder what life must be like under water like that.
Indeed, it's a busy life, for when a loon is diving, it is actively pursuing a meal. Their diet is almost exclusively fish and they actually catch and swallow them without surfacing. A loon caught in a fish net off Chatham had fifteen four inch flounders in its gullet, in addition to a full stomach with more fish.
Loons may weigh as much 15 pounds. Even so, they are strong fliers, navigating the air as a high powered cruiser plows the sea. Landing and taking off are a problem though and in reality, a loon stuck on land is a sad prisoner, unable to take off unless it can reach water. They need a long runway to become airborne. Their legs, designed for power under water, are placed so far back on their body that walking on land is impossible. They propel themselves forward with frog-like hops.
On Nantucket, we usually see Common Loons in winter plumage. Then they are mainly dark gray above with a white chin and breast which occasionally gleams in the sunlight as the birds roll around in the water when preening. In fact it is not uncommon to see them swimming in circles with one webbed foot held in the air as they perform their ablutions. Now in the spring, the adults are getting their white checkers on their backs and the gray colors are being replaced by jet black. A breeding plumage loon shows a sharp contrasting line between the black on the throat and the white breast.
Male and female loons look so much alike that only one loon can decide another's gender. But once that determination is made, it is crucial, for loons mate for life and return every year to the same spot to nest. Loon nests are large circular masses of wet, soggy, half-rotten reeds, heaped up in shallow water. They also like to nest on old muskrat houses. When their eggs hatch, the young are immediately able to dive and swim.
As I said earlier, they eat mainly fish, but will try other things. An inexperienced loon was once observed trying to open a clam with its beak. The clam was too strong for it and the bird lost part of its bill as a result. But this is a minor problem compared with acid rain and pollution, which have reduced its breeding range. At least they are no longer the target for 'sportsmen'.
Hearing the call of a loon on Nantucket is a special treat. They're just practicing here since their nesting territory is up on the lakes of Northern New England. Still, if you are walking the island shores from early March until the start of May, you may hear this eerie and haunting cry. Our loons leave us during the summer, but look for them to return with a crop of newly hatched offspring in October.
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.