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May 26, 1963 - Why Do Birds Sing? Wood Thrush in Song Exclusive Sunday Review sketch by Dennis Puleston of Brookhaven Focus on Nature I am sure you will all be glad to hear from our guest writer, Melita Hofmann who has taken time out of her busy schedule of writing a new book on nature for Doubleday to bring us this week's article, Why Do Birds Sing? You will remember her for her previous articles and especially her "Book of Big Birds" that she wrote and so adequately illu- strated. ps. GUEST WRITER MELITA HOFMANN Why Do Birds Sing? The song of a bird is perhaps the most wonderful thing about it — other than its ability to fly. Each kind of bird has its own special song. Many birds have a number of different songs. We often think that all birds' songs are purely joyful songs. Their singing in the Spring may make us say, "Oh, how happy t h e birds are to be back!" Scientists have discovered, though, t h a t birds express many things, how- ever their feelings and actions are instinctive. A bird chooses a territory, a certain piece of land, bush or tree, in which a nest is to be built, and instinctively sings a warning for other males to stay away. Or he may be daring them to come and fight. To protect the family food supply is a n o t h e r reason or .causelof birds' songs. And so the bird sings to t e 1 1 those of the same species to stay away. Birds of other species may come into his territory and settle if they wish. His song doesn't seem to affect them; and he doesn't mind them for they are not apt to eat the same foods that he might wish to reserve fork is mate and a future family of baby birds. Or perhaps they hunt in different ways or loca- tions. Some hunt for food only on the ground, some in t h e bark of trees, others catch in- sects on the 'wing, etc. So ap- parently his song is meant just for his own kind or specie. At the same time his song signals to female birds vAso may be near, becoming more and more intense. Often the highest perch available is selected by this determined bird to deliver its song! Although some birds deliver their songs of mat- ing or' announcement of terri- rial rights from the tlree tops, bthers sing on the ground. Scientists have also - found' that birds are very sensitive to at- mosphere such as sudden and un- by Paul Stoutenburgh, Cutchogue expected changes of atmosphere like sunlight after a storm. Light suddenly cast upon the retina of birds' eyes will cause them to burst into a song. Birds l o v e sunlight. Often, too, if a stormy wind blows, like a strong easterly wind, birds may become entirely silent. Even if at this time a bird is talking its territory it will of- ten remain quiet until the east wind is gone and the sky is clear again. The changing l i g h t of evening causes birds to sing, too, j u s t as when the stars a r e fading into the early l i g h t of dawn a whole chorus of b i r d voices commences to sing. The blackbird and the lark are the first to sing in the morning. As the earth gathers more light from the sun, more and more birds join with joyful sounding songs. The chorus at night takes on a quieter tone until one by one all become quiet. The quality of a bird's song, also, is af- fected by the atmosphere which surrounds it in its environment. Scientists have found that a city bird doesn't usually sing as clear- ly nor as spontaneously as a bird that lives in the open country. Songs of birds are as varied as the birds are themselves. Each bird has its own special song. The song of the wood thrush is one of the most melodious of all. Its clear bell -like tones c a r r y great distances. The song sparrow has songs of many melodies and rhythms, but the warblers' songs have no melody at all though their singing is irrepressible. And some birds, like the mockingbird, imitate sounds they hear about them such as other birds and even man -made sounds. Most birds can make other sounds than singing just as you can. Some are pitched high, some are low, and some are barely heard, if at all, by human ears. But its song is its voice although it doesn't have a voice box as we have. The bird has a thin membrane, called a syrinx, at the base of its throat. With this syrinx, by controlling the muscles around it, birds are able to make various tones. When the membrane v i b r a t e s it in- creases or decreases the pitch; the rate of vibrations controls the pitch of the song. Being h i g h strung, nervous individuals, birds become greatly excited at times, causing them to burst into song. Excitement increases the rate of ivibrations and thus increases the Pitch. Many birds can sing trills, and many variations of the same song. Other factors which make for variations in the pitch of a bird's song are the diameter and the length of the air passages in its throat. The size of the bird's resonating chambers affect it also, as do the size and age of the bird itself. The songs of young birds are not as perfect as adult's songs. Birds, it has been thought, inherit certain calls, but scientists believe that birds must a 1 s o learn to sing perfect songs: that young birds learn by listening to their parents and to other older birds. If you think about it you will see that a bird's song has a defi- nite reason and purpose. If you have listened to a barnyard hen you know that she has in any sound, even though they may not be songs. But this will help you to realize that a mother bird is much the same as -the mother hen in the songs she sings and the sounds she makes to her young. The hen calls to her chicks with one kind of sound. She g i v e s another sound when a hawk is hovering overhead threatening her and her young with danger. And if she is caught she gives an entirely different, frantic, terri- fied sound. Why not try listening to the birds around you and see J you can tell what they are saying. Many birds that are disturbed by a man or an animal give alarm notes to warn their mates or their babies. The s c o l d i n g chatter of the house wren is an alarm or an attempt to d r i v e away the intruder. The bluejay, too, has several songs that warn all the wildfolk that danger is at hand. Many birds utter single notes or trilll notes for various purposes. A bird's song might be saying to its mate: "Here I am, over in this bush! ",Easy to iden- tify are the hunger sounds of baby birds, or their. w o r r i e d chirps when they suddenly wonder where Mother Bird has gone. The call of the parents, too, keeping their brood together, can be identified by you, if you listen, perhaps to a family of ducks, or quail... quietly a n d gently, sometimes sharply scold- ing. And there are sounds that birds make to keep a migrating flock together. The best example is the sound of geese l I y i n g High overhead when their "honk - honking" can be heard even be- fore you are able to find their V- formation in the sky. But these are sounds not to be compared to the high notes of the gold- finches gathered together in a tree top s i n g i n g a delightful chorus at migration time or at nesting time! Or of a flock of bobolinks' wild sweet songs as they fly across a field, or of sev- eral robins vieing with one another, in clear happy sounding tones, an endless variation of themes for a half or more without stopping! Can you guess what they are saying? FIELD OBSERVATIONS Judd Bennett reports: May 20 — East Marion White-crowned Sparrows Bob- o-link (150) Golden- winged Warbler Prairie Warbler Blackburnian Warbler Worm - eating Warbler Black- throated Blue Warbler Scarlet Tanagers Woodcock (on nest) Laurence Ernest .reports: Southemptoa May 11 - 14 Rose,brea.Ved Grosbeaks (4) Rou- winged Swallows Gol nGh Kingfishei!` ' Broad_ winged Hawk Swamp SIPIrrows Purple Finch Hermit Thrush (2) Nashville Warbler Cape May Warblers Magnolia Warbler Canada Warbler Black- throated Blue Warbler Black - throated Green Warbler White -eyed Vireo Yellow - throats Dennis Puleston reports: Moriches — May 13 Oystercatchers (2) Brookhaven _ May 14 White-crowned Sparrow (2) Sharp - tailed Sparrow Northern Phalarepe Say"k May 16 Cerulean Warbler (2) Sayville — May 17 Least Flycatcher Yellow- throated Vireo Jamaica Bay Sanctuary — May 18 Glossy Ibis (5) Knot Blue- winged Teal (3) Sayville — May 19 Bay - breasted Warbler (many) Tennessee Warbler (many) Cape May Warbler (many) Nashville Warbler Wilson's Warbler (2) Hooded Warbler Warbling Vireo Olive - backed Thrush Gray-cheeked 'Thrush Golden- winged Warbler Ruby-crowned Kinglet Sayville — May 20 Canada Warbler (5) Hooded Warbler Philadelphia Vireo