To read some of our books on ornithology, would lead one to suppose that birds of the same species constructed nests exactly alike, but the fact is, that no two nests are alike. A bird will improve in nest building, usually, with age. I have a little friend, a chestnut-sided warbler, that has constructed twenty-three nests since I made her acquaintance. As I remember them the last nest is the neatest and most substantial. Some have been made almost wholly of rags. Chickadees have adopted cotton-batting, and call for it if I neglect to keep it in the dooryard. It often happens that birds select new material, if handy, instead of hunting the usual nest building material. If birds were guided by instinct and did not exercise reason, they would select the same nesting material year after year. The habit would be so securely fixed that the bird would not be tempted to use new material, no matter how plentiful or handy it might be. The fact that birds readily accommodate themselves to new surroundings, is proof positive that they possess the power to reason. I found a nest, last season, of the wood-thrush, which was a complete departure from the usual nest. The bulk of the nest was composed of moss, sphagnum. It was placed on some bushes of the black-alder which the snow had bent down. Instead of mud the bird had used a black soil, and the nest was lined with horsehair. The horsehair, moss, and black mold were all near the nest. If I had found the nest after the young had left it, it would have proved a puzzle for me. As it was, the old bird was on the nest when I found it and so gave me the clue.
Young birds are taught to sing by the old males. This is true of the birds that have come under my observation. Even the grouse teaches the young to drum. This is done soon after dark in the fall of the year. From my hammock I often hear these lessons. The old grouse makes the woods ring with his drumming. Then he rests while the young grouse try a hand. Their efforts are not a success, and the old bird again shows them how to do it. Some nights this will go on for two hours.
There is a test that any one can try, to prove that song is educational and not instinctive.
Go into the woods inhabited by the wood-thrush, and sit down and listen. It will soon be evident that you have invited yourself to a bird's singing school.
In a party of summer residents from Magnolia, there was one lady who told me she had no patience with my views on song. That a bird would sing, anyway, because it had a throat adapted to song. She said that when I heard birds sing out of season, I would claim that they were teaching their young, when in fact they were only exercising their voices without a thought of teaching. When they were ready to return to Magnolia, I offered to show them a path through the woods, a new way to them. When I had reached a spot where I knew there was a family of wood-thrushes, I ordered a rest. When we had become quiet the old thrush tuned up and gave us the song. It is a short song, but loud, clear, and flute-like. There was no wind, and the song appeared to be sweeter and louder than usual. When the old thrush had ceased, one young bird after another took up the strain. Some would give one note, others two or three notes. Some notes would be hoarse, others would be shrill. After awhile the birds would forget the lesson and drop out one after the other. When all were silent, the old thrush would again give them the right pitch and tone, and again the young thrushes tried to imitate the singer. For two hours we sat there and listened. The lady had to admit that the old bird was giving the young birds a lesson. Yet she claimed that the thrush was an exception. I was glad that she was ready to admit that one bird of a species was intelligent. I told her that when she had devoted two hours to all the other birds she would be converted to my faith.
THE HERMIT THRUSH.