Read Ebook: Food Habits of the Thrushes of the United States by Beal F E L Foster Ellenborough Lascelles

Font size: 10 px 15 px 20 px 25 px 30 px 35 px

Background color: BlackWhiteGrayLight GrayDark GrayDim Gray

Text color: BlackWhiteGrayLight GrayDark GrayDim Gray

Apply/Save settings

Ebook has 88 lines and 22365 words, and 2 pages

Page.

Introduction 1

Townsend's solitaire 3

Wood thrush 5

Veery and willow thrush 9

Gray-cheeked and Bicknell's thrushes 11

Olive-backed and russet-backed thrushes 13

Hermit thrushes 18

WASHINGTON GOVERNMENT PRINTING OFFICE 1915

UNITED STATES DEPARTMENT OF AGRICULTURE

BULLETIN No. 280

Contribution from the Bureau of Biological Survey

HENRY W. HENSHAW, Chief

FOOD HABITS OF THE THRUSHES OF THE UNITED STATES.

INTRODUCTION.

North American thrushes constitute a small but interesting group of birds, most of which are of retiring habits but noted as songsters. They consist of the birds commonly known as thrushes, robins, bluebirds, Townsend's solitaire, and the wheatears. The red-winged thrush of Europe is accidental in Greenland, and the wheatears are rarely found in the Western Hemisphere except in Arctic America. Within the limits of the United States are 11 species of thrushes, of which the following 6 are discussed in this bulletin: Townsend's solitaire , the wood thrush , the veery and willow thrush , the gray-cheeked and Bicknell's thrushes , the olive-backed and russet-backed thrushes , and the hermit thrushes . An account of the food habits of the 5 species of robins and bluebirds appeared in Department Bulletin No. 171.

As a group thrushes are plainly colored and seem to be especially adapted to thickly settled rural districts, as the shyest of them, with the exception of the solitaire, do not require any greater seclusion than that afforded by an acre or two of woodland or swamp.

The thrushes are largely insectivorous, and also are fond of spiders, myriapods, sowbugs, snails, and angleworms. The vegetable portion of their diet consists mostly of berries and other small fruits. As a family thrushes can not be called clean feeders, for the food eaten often contains a considerable proportion of such matter as dead leaves, stems, and other parts of more or less decayed vegetation. It might be supposed that this was gathered from the ground with insects and other food, but investigation shows that much of it has a different origin. It was noticed that the setae or spines of earthworms were a very common accompaniment of this decayed vegetation. Earthworms themselves are rather rarely found in stomachs, although some birds, as the robin, eat them freely. It is well known that the food of earthworms consists largely of partially decayed vegetable matter found in the soil. Hence it is probable that decayed vegetation found in the stomachs of thrushes is the food contained in the earthworms when they were swallowed. The tissues of worms are quickly digested, leaving the contents of their alimentary canals mixed with the hard indigestible setae or spines.

The thrushes are pronounced ground feeders, and may often be seen picking small fruit that has fallen to the ground. The vegetable portion of their food is largely composed of fruit, which constitutes over 34 per cent of the total food. Of this 30.88 per cent is made up of wild berries, which outweigh the domestic varieties with every species. In all, 94 species of wild fruits or berries were identified in the stomachs of these birds, although it is not always practicable to identify such material unless seeds or some other characteristic parts are present. As this is not often the case, a considerable portion of the stomach contents must be pronounced "fruit pulp" without further identification; thus probably many more species are eaten than are recorded. Moreover, in the case of some fruits, it is not possible to distinguish species by the seeds, so that many species go unrecognized except as to genus. Domestic fruits are eaten so sparingly by the thrushes here considered as to be of no economic importance.

Note.--This bulletin treats of the economic relations and value to agriculture of the thrushes of the United States other than robins and bluebirds. These two forms were discussed in Department Bulletin No. 171, issued February 5, 1915.

TOWNSEND'S SOLITAIRE

Townsend's solitaire, a bird of the far West, is a resident of high mountains and lonely gorges. It is partial to running streams and often builds its nest just above a rushing mountain torrent. It ranges from Alaska through the Sierras south to San Bernardino, Cal., and through the Rockies to Arizona and New Mexico, and occasionally farther east. The species is not evenly distributed over this region, but is restricted to such high mountainous portions as afford its favorite surroundings. As long as it retains these habits the bird will have little or no effect upon the products of husbandry, and its food can have only a scientific interest. The song of this species is said to be at times the finest of any of the thrush family.

As this bird is comparatively rare in settled regions only 41 stomachs are available for determining the character of its food. The most southerly and easterly one was taken in Texas, the most westerly in California, and the most northerly in Wyoming. They are distributed through all the months of the year, although April and May are represented by but one each and December by but two. Every other month has three or more. An investigation based upon such limited material can be considered only as preliminary, but will serve to show some of the more important elements of the food. This was made up of 35.90 per cent of animal matter to 64.10 of vegetable.

Hemiptera were found to the extent of 3.51 per cent of the total food. All were contained in three stomachs taken in March, June, and July. In the July stomach four cicadas, or dog-day flies, constituted the whole contents. Grasshoppers amount to less than 1 per cent and all other insects to but a trifle. Spiders were eaten to the extent of 2.94 per cent of the food and were found in the stomachs taken in seven of the twelve months, and judging from their distribution they are eaten whenever available. A hair snake was found in one stomach. Following is a list of insects identified and the number of stomachs in which found:

COLEOPTERA.

HEMIPTERA.

Rocky Mountain cedar 3 Western cedar 1 Other cedars 2 Hackberries 1 Douglas hackberries 1 Service berries 1 Rose haws 2 Wild cherries 1 Sumac berries 1 Poison ivy 1 Waxwork 1 Madrona berries 5 Honeysuckle berries 1 Elderberries 1 Fruit not further identified 3

WOOD THRUSH.

The wood thrush is distributed over the eastern part of the United States wherever suitable conditions are found. It is a lover of open groves and bushy pastures, and may be found along little-traveled roads and near low bushy swamps. The bird is noted for its sweet song, and many country people who are well acquainted with its notes know little or nothing of the bird itself. Its favorite time for singing is in the early evening at the close of a sultry afternoon when a shower has cooled the air. As a rule, it does not nest in gardens or orchards and is seldom seen about farm buildings. It is strictly migratory, and the greater number pass out of the United States in winter, though a few remain in the Southern States. It usually migrates north in April or early May.

For the investigation of the food habits of the wood thrush 171 stomachs were available. One of these was collected in Florida in January and another in Alabama in February, and these two will be treated separately. The remaining 169 were collected from April to October, and are fairly well distributed over that time. The food consisted of 59.59 per cent of animal matter to 40.41 per cent of vegetable. The greatest quantity of animal food was eaten in April, the month of arrival from the south, and the least in October, the month of the return migration.

Following is a list of the insects identified in the stomachs of the wood thrush and the number of stomachs in which each was found:

HYMENOPTERA.

COLEOPTERA.

HEMIPTERA.

ORTHOPTERA.

ISOPTERA.

Following is a list of fruits, seeds, etc., identified and the number of stomachs in which found:

Yew berries 1 False Solomon's seal 1 Bayberries 1 Mulberries 10 Spiceberries 5 Currants 1 Mountain ash 2 Service berries 2 Blackberries or raspberries 17 Rose haws 1 Wild black cherries 1 Chokecherries 7 Domestic cherries 4 Croton 1 American holly 2 Woodbine berries 1 Frost grapes 4 Wild sarsaparilla 1 Flowering dogwood 3 Rough-leaved cornel 4 Dogwood 1 Black gum 1 Huckleberries 1 Blueberries 6 French mulberry 1 Black elderberries 1 Other elderberries 3 Fruit pulp not further identified 12

Of the two stomachs not included in the foregoing discussion, the one taken in Florida in January contained 93 per cent of wild fruit and 7 per cent of weevils, wasps, and spiders; the one collected in Alabama in February was entirely filled with animal food, of which 88 per cent was caterpillars, 5 per cent May beetles, 6 per cent bugs, and 1 per cent spiders.

VEERY AND WILLOW THRUSH.

The veery is distributed over the eastern portion of the United States during migration and breeds in the Northern States as far south as Pennsylvania, and in New England and Canada. In winter it disappears almost entirely from the country, only a few remaining in Florida and perhaps in other Southern States. Its western representative is the willow thrush. Like other thrushes, birds of this species are shy and retiring in disposition, keeping for the most part in the shade of woods or bushy swamps, or building nests in a damp ravine with a brook gurgling past. They have been known, however, to visit orchards and sometimes gardens which are not kept too trim. It is thus evident that the food has little direct economic interest, as this bird does not come in contact with the farmer's crops.

For investigating the food of the species 176 stomachs were available. They were collected during the seven months from April to October, and represent 18 States, the District of Columbia, and Canada. The food separates into 57.27 per cent of animal matter and 42.73 per cent of vegetable. The former consists mostly of remains of insects, and the latter of fruit.

Lepidoptera are, next to Hymenoptera, the favorite insect food. They were eaten in goodly quantities in every month except October. The average for the season is 11.91 per cent. Grasshoppers appear to some extent in every month except April, the greatest consumption taking place in October , but as only small numbers are eaten in the earlier months the aggregate for the year is only 4.91 per cent. A few other insects of various orders amount to 0.98 per cent. Spiders are eaten regularly and constantly through the season, except that none were taken in October. A few sowbugs, snails, etc. , complete the quota of animal food. Following is a list of insects identified and the number of stomachs in which found:

HYMENOPTERA.

COLEOPTERA

DIPTERA.

Besides fruit, the veery eats a few seeds of grasses and weeds and a few of sumac, but none of the poisonous species were found in the stomachs. These seeds were eaten so irregularly as to suggest that they are merely a makeshift taken for want of something better. Rubbish , consisting of decayed wood, bits of leaves, plant stems, etc., completes the vegetable food.

Following is a list of the items of vegetable food and the number of stomachs in which found:

Yew berries 1 Pigeon grass seed 1 Rush grass seed 1 False Solomon's seal 1 Greenbrier berries 2 Hackberries 1 Poke berries 3 Spice berries 2 Service berries 3 June berries 9 Mountain ash 1 Crab apples 1 Strawberries 3 Blackberries or raspberries 8 Wild black cherries 1 Bird cherries 1 Chokecherries 1 Staghorn sumac 2 Dwarf sumac 1 Three-leaved sumac 1 Other sumac 1 American holly 1 Woodbine berries 1 White cornel 2 Alternate-leaved cornel 3 Rough-leaved cornel 1 Dogwood berries 2 Sour gum berries 1 Huckleberries 1 Blueberries 4 Snowberries 2 Black elderberries 2 Red elderberries 4 Other elderberries 3 Fruit pulp not further identified 4

GRAY-CHEEKED AND BICKNELL'S THRUSHES.

The gray-cheeked thrush is found in migration over all the Eastern States, but breeds farther north, beyond our limits. Bicknell's thrush , a closely related form, while having somewhat the same general range, breeds farther south and nests in the mountains of northern New York and New England. Both subspecies have the same general habits as other forms of the genus so far as haunts and choice of residence are concerned, but their far-northern range excludes them from coming into contact with cultivated crops. The species does not seem to be very abundant anywhere, and consequently only a few stomachs have been received for examination. In all they number but 111 and are very irregularly distributed in time. None were taken in August and only one in July and two in June. From so scanty and unevenly distributed material it is impossible to draw final conclusions, but we can get some idea as to the nature of the bird's food and its economic importance.

Share on: WhatsApp @Hash Facebook Tweet