As the temperatures began to rise during the month of March, tracks of open water started to appear in the lengthy ice cover of the St. Louis River. The days continued to get longer, and by late in the month, these sites of open water held flocks of early water birds. Every few days more would appear.
Starting with a few Canada geese, these flocks were quickly mixed with some ducks: mallards and goldeneyes (which often winter in the non-frozen waters of Lake Superior). March is replaced by April, and the waterfowl types continue to arrive. Often by the middle part of this thawing month, we may see a dozen or more kinds.
The flocks of Canada geese are still with us, but are joined by groups of cormorants, tundra swans, white pelicans and several kinds of ducks: ring-necked, scaup, shoveler, teal, bufflehead, wigeon and wood ducks. Grebe and great blue herons are here, too, but they are usually alone.
Along with this variety of interesting aquatic feeders are the three kinds of mergansers: common, red-breasted and hooded. Mergansers are frequently seen in the larger bodies of water where they dive to feed on fish. Unlike other water birds, mergansers have small rough teeth along the sides of their bills. Such a unique mouth style has given them another name: sawbill. The rough teeth are not used for chewing, but allow the birds to grasp and hold onto their slippery fish catches.
All three kinds are common in the Northland, and their small flocks usually arrive in the cold water of April. Largest and most abundant is the common merganser. Males have a dark head and back, but much white below. Females with their reddish head and a crest look almost like another kind of bird. Both are about 18 inches long. The red-breasted merganser is nearly the same length as the common merganser. Females are much like their common cousins, but the males sport a crest on their dark heads with a red chest pattern. It is easy to confuse the females of these two kinds of mergansers.
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Hooded mergansers are easy to tell from these two larger mergansers. They are shorter, only 13 inches long. The underside is light brown, back is dark like the others, but the head pattern is quite different. Males hold a large white patch on the side feathers above and behind the eyes. When trying to get the attention of females, they will display these feathers and make their heads appear much larger than before, hence the "hooded" name. Female hoodies are more of a brown color and do not show this head pattern.
All three species come back to the Northland in spring from wintering in the south; often as far as the gulf. Though many keep going north to breed in the lakes of Canada, others remain here. Now, as they pause and feed on their journey, they make for interesting and enjoyable waterfowl watching as the ice breaks up.
Larry Weber is author of the "Backyard Almanac" and "Butterflies of the Northwoods." He lives in Carlton County and teaches natural science at Duluth's Marshall School.
