Diary entry, Oct. 1, 2011 - "Saw and heard my first flock of Canada geese heading south."
October is the month that we begin to see many migrants heading south. By the end of October, I usually write in my diary that I have seen my first rough-legged hawk of the fall. Some of these hawks have traveled from the far north into the U.S. to set up their winter territories.
The rough-legged hawk's scientific name is Buteo lagopus. Buteo is Latin, meaning a kind of falcon or hawk; lagopus comes from two Greek words - lagos, meaning a hare, and pous, meaning foot or hare-footed.
The feathers on the bird's legs and feet resemble that of a hare's furry foot. This also is where the common name of rough-legged comes from.
The rough-legged is a large hawk from 19 to 24 inches long, with a wingspan of 48 to 56 inches. This hawk also has relatively longer wings and a longer tail than most buteos.
If you watch a large hawk that appears similar to the American kestrel hovering in one spot over an open field, it will be the rough-legged hawk.
However, the coloring can confuse you - the hawk has two color phases. In its dark phase, the body is a dark brown above and below but usually shows much white at the base of the flight feathers. In the light phase, it has a brown back and wings, with the head, neck underparts and thighs a white to buffy color. The white phase has conspicuous black patches at the wrists, or bends, of wings.
The rough-legged sometimes will spiral high up in the sky until only a speck can be seen; however, when hunting for mice it alternately will flap and glide close to the ground, a behavior that is similar to that of the marsh hawk.
The rough-legged hawk has weak feet that only are capable of killing small animals.
Like the rough-legged, some other birds have two or more color phases. For example, the snow goose has white and blue forms. For years, they were thought to be a separate species but now are classified as the same species.
Genetic studies done in 1968 found that the birds are one species and when the two interbreed, the blue phase is dominate over the white.
Having two color phases is called dichromatism, which comes from two Greek words: dicha, meaning two, and chroma, meaning color.
Some birds, such as the screech owl, have more than two color phases. This is called polychromatic, which also comes from two Greek words: polys, meaning many, and chroma, meaning color.
The difference between two or more phases has nothing to do with age, sex or time of year. It is an inherited year-round color.
Some color phases are influenced by the climate. For instance, the screech owl has three color phases in the eastern U.S.; however, it has mainly two colors - a red phase and a gray phase - while an intermediate brown makes up a small percentage of the population. The red phase is more abundant in the south while the gray phase is more prevalent in the north.
My favorite game bird, the ruffed grouse, is polychromatic, with two extreme gray and red phases and also an intermediate color. These color phases are similar to the screech owl phases, with the gray phase more prevalent in the north.
Dimorphism is another color phase, which is the term for changes in plumage of birds in response to seasonal changes. Dimorphism comes from two Greek words: di, meaning twice, and morphe, meaning form.
Some birds in the far north have a pronounced seasonal dimorphism, with the ptarmigans the most well-known of these birds. They are white in winter, brown in summer and, in between, there are two or three other feather plumages. These different plumages blend in with the environment to hide the birds from predators.
The length of day is the main controlling factor in this plumage change; however, the male ptarmigan remains white, while the female turns brown during brooding time. With the male remaining white, this make him highly conspicuous to predators, especially the golden eagle. Biologists call this deflective adaptation, which means that the white coloring deflects attacks of predators away from the brown-colored females to the more conspicuous males, who are biologically less valued than the brooding females.
The more I read about God's creation, the more I am held in awe with nature.
Bower retired after 34 years as a wildlife conservation officer for the state Game Commission. He has published several books about his experiences, the latest being ''Every Day Was Game Day.'' Questions and comments may be sent to him at 153 Redington Ave., Troy PA 16947.