Foam Lake Birding No. 17

No. 17
This week’s bird, the American Crow, needs no introduction. Again, it is another of those New World birds that have the adjective, American, added because of several, already named, European crows. Later, it was discovered that there actually were two other crows in the Americas that needed names – The Northwestern Crow and Fish Crow. The Fish Crow occurs along the coast and big rivers of the southeastern USA; the Northwestern Crow occurs along the coast and islands of British Columbia. The American Crow exists across most of North America.
The American is bigger than the other two, but there is so much size overlap that they cannot be separated in the field, even in mixed flocks. The only way to tell them apart is by their sounds. Only the American makes a clearly pronounced caw. So, if anybody happens to be in BC and hears a crow making a “funny” sound, it is a Northwestern (similarly with the Fish Crow in the southeastern USA). There is no need to use binoculars as there are no visible differences among all three.
In addition to the three crows, there are two ravens, the Common and Chihuahuan, that add to the confusion. Locally, there are only two birds, the Raven (Common) and the Crow (American) that make identification difficult. The Raven is considerably larger than the Crow, but as previously stated, size is of little use in the field. Obviously, colour is of no use whatsoever. How does one tell them apart? Sound, if the birds cooperate, is the easiest and the best. Ravens croak; Crows caw. If the birds are silent, distinguishing characteristics are subtle indeed! When perched, the Raven has more of a “Roman nose” shaped beak and visible (usually) fluffed out throat feathers that somewhat resemble a beard. The Crow is more streamlined. In general flight, the Raven’s wings are longer and more slender; the body length is longer, especially the head and neck, in proportion to the wings. In overhead flight, the Raven’s tail is quite rounded; the Crow’s is square. In flight toward or away from an observer, the Raven’s wingbeat is flatter and shallower. When coming to a landing, the raven’s wings are extended straight out; the Crow’s wings are lifted slightly upward in a shallow “V” (dihedral). If Ravens or Crows are quartering away or toward an observer it is almost impossible to tell them apart. Often ravens will soar high in the sky like hawks; Crows never do.
As a birder, I am glad that these two birds exist side by side as it were. It gives me a chance to improve my identification skills by forcing me to concentrate on things other than colour, feeding habits and habitat. Focusing on small and subtle details makes it much easier to identify other birds that are similar to each other.
Crows are moderately migratory flying south just to the edge of the snow line. Locally, there is some consolation in that a large black bird seen in the winter is positively a Raven. People in the Maritimes are not so lucky. There, Crows and Ravens are resident year round! This week’s photo was taken in Prince Edward Island in October of 2007.
Crows, along with ravens, magpies and jays belong to a group of birds called Corvids (from Latin for crows). Because of West Nile Disease, the word, Corvid, has become familiar to just about everybody. Corvids carry the west Nile virus. Mosquitoes bite the Corvids, then, bite other birds and animals thus infecting them. Most birds and animals are immune to the disease, but those that are not become casualties. Some bird species have been decimated by the disease. Generally speaking, it could be argued that man is immune. However, some people get sick with West Nile every year and a few of those, unfortunately, die. This year, it has declined sharply.
Overall, Crows (Corvids in general) are a beneficial lot. They feed on insects, carrion, man’s refuse and, unfortunately, eggs and young of other birds. Their diets are almost identical to that of the gulls. Being the most intelligent of all groups of birds, they have learned to live very comfortably near man. European traditions, which were carried over to the New World, always painted large black birds as being somehow evil. They are not. Rather, they are intelligent which makes them difficult for man to control, which in turn makes them unpopular. Of all birds, they are probably, the most interesting to observe.