The Mergansers - "Fish Ducks!"

By Al Lowe
Contributor

Mergansers are often sneeringly referred to as 'fish ducks'. This name is entirely appropriate, as a good portion of their diet is made up of no personal experience of it, that a merganser, when cooked, tastes awful - sort of a mixture of very old fish and rancid butter.
There are three species of mergansers in Canada, and we have them all in Northwestern Ontario. They are the Common Merganser (Mergus merganser), the Red-breasted Merganser (Mergus serrator) and the Hooded Merganser (Lophodyted cucullatus). All three of these species are fairly similar. This is especially true of the females, which are very close to being look-a likes. The female Hooded has a darker head and larger crest than the others. The differences between the other two are quite small. If you are a dedicated birdwatcher you can distinguish them - if you are really alert. If you are casual about the whole thing, just forget it as far as these two are concerned.
The male birds are a little easier. First, the Hooded, in his spring plumage, has a very large, prominent black and white crest, which is unmistakable, even in flight. The Red Breasted has a green head which is also crested, but in a shaggy sort of way. Its upper parts and wings are fairly dark. The Common drake also has a green head, but with hardly any crest. It also has a lot of white on its back, sides and wings. So you can tell the drakes apart quite easily - in the spring, that is. In the fall, when all ducks are in their eclipse plumage, all of them are mottled brown and are rather scruffy looking.
Mergansers all have beaks which are designed for catching and holding fish. The end of the beak is hooked, and the sides are very heavily toothed. These birds are good divers and can swim well under water. Their diet is not entirely fish, as they also eat insects, crayfish and so on, as well as some vegetable matter. In Scotland, as well as in parts of the Maritimes, they are highly disliked because of a supposed fondness for young salmon. In real fact, mergansers feed largely on much slower, easier-to-catch fish, such as suckers, and others of that type.
Two of these species nest mainly in hollow trees - the Hooded and the Common. The other one prefers locations under stumps or hollow logs. They lay about a dozen eggs on the average. Merganser families are rather odd in the way in which they handle their ducklings. Any female will freely adopt any other female's young. So you may see one duck with only three or four of the ducklings, and another with 20 or 25. You may also see a duck with one group of ducklings which are obviously younger or older than the rest of the brood. She has borrowed or adopted them from another mother sometime. One day a while ago, I counted 36 ducklings with only one old duck anywhere in sight.
People in boats sometimes find it a great sport to chase mergansers around the lake, just for fun. You should know that these birds, like most others, are protected by the Migratory Bird Act against 'molesting' or 'worrying'.
Our three mergansers could not in any sense be considered as game birds, but they are an integral part of the ecological makeup of Northern Ontario. So just leave them alone - they are intriguing to watch.