Birds Useful to the Gardener

From the bluebird to the robin, each of these birds provide a value to the gardener in one form or another.

July 27, 2012

Although March is now behind us and April is with us once again, I still carry with me the memory of one morning in early March when suddenly I saw a flash of cerulean color among the naked branches of a roadside maple. I knew then that spring was just "around the corner” for had not the bluebird arrived from his winter's stay in the southland?

We welcome this lovable bird with his soft warble and gentle manners for, with the exception of the robin, no other bird shows such a decided fondness for human society. If we place a birdhouse on a nearby tree or on a tall post he will quickly take possession of it and throughout the following weeks will reward us with many, delightful moments for having provided him with a ready-made home. 


Indeed, he will do more than entertain us; he will also help us to get rid of various insect pests that make gardening or farming so discouraging at times. He is one of our truly useful birds and I know of no one who has accused him of stealing fruit or preying upon crops. His diet consists mostly of insects (about 68 per cent) and their allies, such as spiders and myriapods, and such vegetable food as he does eat—pokeberry, partridgeberry, greenbrier, chokeberry, Virginia creeper, bittersweet, strawberry bush, wild sarsparilla, wild spikenard, sumach, rose haws, sorrel, ragweed and grass— are of little value to us. He is of particular service in August and September for then grasshoppers make up about 53 per cent of his diet. Those of us whose orchards are overrun with harmful insects, caterpillars and others, would do well to cultivate the friendship of the bluebird for he will repay any kindnesses we extend to him many times over by destroying our insect enemies. 

The bluebird is the first of our migratory song birds to return from the south but is closely followed by the robin, perhaps the best known of all our birds since his distinctive plumage, his reputation as a harbinger of spring (which is more deservedly the bluebird's) and his fondness for  human society make him familiar to all. 

Originally Published in Organic Gardening April 1946.

The robin has been indicted as an enemy because of the great amount of small fruit which he eats. It has been shown by stomach analysis that vegetable food comprises about 58 percent of his diet, 42 per cent or more being wild fruits and only about 8 percent being possibly cultivated varieties, although this amount increases to about 25 percent in June and July.  The reason for the sharp increase in these two months is possibly due to the fact that the bird up to this time has been feeding on insects, earthworms and dried berries and being satiated with such fare finds the early ripening cherries and other small fruits rich juicy morsels too tempting to pass up. He has not been found guilty of eating apples, peaches, pears, grapes or even late cherries because by the time these fruits ripen the woods and roadsides are teeming with such wild fruits as dogwood, greenbrier, barberries, hackberries, elder, wild cherries, wild grapes and others which are apparently more to his taste. If such wild fruits are not abundant and the robin takes to eating cultivated fruits we ourselves are to blame for having destroyed the wild fruits and berries which form his natural diet. 

If we have thus made him an unwilling pest, the robin himself wishes to have it otherwise and attempts to offset the harm he unwittingly does by destroying enormous quantities of noxious insects. For those statistically minded the remaining 42 percent of his food consists mainly of insects, broken down as follows: beetles 16 percent; grasshoppers 5 per cent, although this increases to about 17 percent in August; caterpillars 9 percent; and various insects, spiders, snails and angleworms 12 percent. All of these insects eaten are not necessarily harmful species, (about 5 percent of the beetles eaten, for instance, are useful ground beetles) but I think it safe to say that a third or more of the insects eaten by the robin can be classified as destructive. 

Robins have been killed because of the ravages which they have committed in some fruit-growing regions. But since they eat ten times as much wild fruit as cultivated fruit it seems inexcusable to destroy these birds in order to save so little, particularly when they make amends by destroying noxious insects. As a matter of fact, the robins, by feeding on such insects, have been helping the orchardists all season to make their crops possible and that when the fruit ripens the orchardists are indebted to them for services rendered. It is, as I see it, wholly unnecessary to destroy the robins at any time or in any region for with a little care and effort both the birds and the fruit can be preserved. If wild fruit is not abundant, cultivated crops can be protected by planting fruit-bearing shrubs and vines to provide the birds with their natural food and which, incidentally, would be ornamental as well, and where fruit is grown in large quantities it would be no great loss to set apart a tree or two for the birds, although in some cases the fruit trees can be protected by scarecrows.

About the time that we catch our first glimpse of the bluebird and robin we may hear the familiar note of the phoebe about the barn, in the orchard, or along the rushing stream. Here indeed is the gardener's real friend for the phoebe subsists almost exclusively upon insects, over 99 percent of his year's food consisting of insects and, more important, the insects eaten are chiefly noxious species. Foremost in the phoebe's insect diet are hymenopterous insects, which are eaten with great regularity and which constitute, moreover, the largest item in every month. A few parasitic species, unfortunately, are eaten but these are more than offset by the vast number of destructive sawfly larvae which are destroyed. Beetles rank second on the list of insect food and include such harmful species as the click beetles, May beetles, corn leaf-beetles, the 12-spotted cucumber beetles, the striped cucumber beetles, the locust leaf miners and such weevils as the notorious cotton-boll weevil, the strawberry weevil and others. There is perhaps no more useful bird around a garden or farm than the phoebe and he should be encouraged to nest in the vicinity by protecting him against cats and other marauders. 

The phoebe among others belongs to a family of birds called Flycatchers and includes, among others, such species as the kingbird and wood pewee. They are all insect eaters and for the most part catch their food on the wing although they will also pick up some insects from trees and shrubs and at times will even descend to the ground in search of such animal forms as millipedes.

The kingbird is a useful bird to have about a garden or orchard, or a poultry yard for that matter, for not only does he destroy a large number of harmful insects but his remarkable courage and persistent aggressiveness in attacking his natural enemies, especially hawks and crows, make him a valuable ally to have around as a protection against such birds of prey that feed on young chickens and other barnyard fowl, to say nothing of our song birds. I have seen a kingbird attack and drive off a cat that was stalking a nestling which had fallen out of its nest, and on one occasion a pair, of these birds pounced upon a hawk that had swooped down upon a flock of young chickens and so buffeted the predator that he was glad to escape without his prey.

A careful investigation of the stomach contents of some 665 kingbirds made by experts of the Biological Survey reveal that about 85 percent of the kingbird's food consists of insects, most of which are harmful species. May beetles, click beetles, blister beetles and weevils are eaten in large numbers, as are wasps, ants and wild bees. During the summer grasshoppers and crickets fill a large part of the menu,as well as leaf hoppers and other bugs. The complaint has been made by beekeepers that the kingbird preys largely upon honeybees. But of the 665 stomachs that were examined only 22 were found to contain honeybees and in these 22 stomachs there were in all 61 honeybees of which 51 were useless drones, 8 were workers and the remaining 2 were so badly mutilated as to be unidentifiable. If the few honeybees that the kingbird eats are debited to his account, he can, on the other hand, be credited with destroying robber flies. These insects prey on honeybees and by reducing their number the kingbird performs a real service to the apiarist. Twenty-six robber flies were found in the 665 stomachs and these, I think, more than balance the 8 worker honeybees.

The entire family of Flycatchers has been indicted as being harmful to honeybees but careful stomach examinations do not sustain this accusation. A few are eaten, of course, but these few are mostly drones or males so that the harm done in this direction is negligible. If the flycatchers do any harm at all it is in the destruction of parasitic and predaceous hymenoptera. So few predaceous hymenoptera are eaten, however, that their loss is of no practical importance. As for the parasitic species, it is true that some are taken by most flycatchers and that considerable numbers are eaten by the smaller species, the wood pewee being probably the worst sinner of the whole family in this respect. It has been estimated that about one-fourth of the ants, bees and wasps eaten by this bird are parasitic species. Theoretically this may seem to be inimical to the interests of the gardener or farmer but practically the amount of damage done may not be as great as is supposed, for it must be borne in mind that the parasitic species destroy useful insects, including other parasites, or are themselves destroyed by other insects. The end result would appear to involve a problem which is so complicated by a number of factors that an exact solution could probably never be arrived at. 

Although there is no question but that the wood pewee does some harm in destroying useful parasitic insects, it must be remembered that the bird destroys many noxious species, such as plum curculios, corn weevils, clover-leaf weevils, rice weevils, horse-flies, robberflies, tree-hoppers, leaf-hoppers, squash bugs, moths and caterpillars.  All in all I think we can condone the loss of a few useful bees and wasps in return for the help which the wood pewee renders in ridding the world of many annoying or harmful insects. In this respect the bird confers a real benefit upon us. 

The wood pewee can be said to subsist almost entirely on animal food since 99 percent of his diet is of animal origin. Another bird that feeds almost entirely on animal food is the house wren. An examination of 52 stomachs showed that 98 percent of the contents was made up of insects or their allies, and only 2 per cent was vegetable matter, including bits of grass and similar material which apparently were taken quite by accident with the insects. Unlike the wood, pewee the house Wren does not feed, as far as is known, on any useful species and for this reason can be said to be entirely beneficial. Half of the bird's food consists of grasshoppers and beetles and "the remainder of caterpillars, bugs and spiders, all with the exception of the spiders being harmful species. These diminutive birds are industrious foragers and overlook no tree, shrub or vine for caterpillars; even posts and fence rails or other crannies or crevices are meticulously examined for insects and for this reason they should be encouraged to nest about our gardens and orchards except when they might unduly interfere with the nesting of other birds for they are pugnacious creatures and will often take to driving away the rightful occupants of birdhouses or other nesting sites. 

There are many other birds that help to keep down the insect population, such as the brown thrasher, the chickadee, the catbird, the swallows, the towhee, the Baltimore oriole, the nighthawk, to name a few. The meadowlark also belongs in this list for this bird is highly useful in devouring ground caterpillars which are habitually overlooked by birds that frequent trees. Crickets and grasshoppers are the most important food item, constituting 26 per cent of the food of the year and 72 per cent of the food in August. Beetles come next and include such harmful species as the May beetles, the grubs of which are among the worst enemies to many cultivated crops, notably grasses and grains, and to a less extent strawberries and garden vegetables. In May cutworms constitute over 24 percent of the meadowlark's diet, and as this is the month when these insects begin their deadly careers the meadowlark at this time renders a distinct service.

Hairy caterpillars, as a rule, are not relished by most birds, but two species, the yellow-billed cuckoo and the black-billed cuckoo, seem to prefer these to the smooth kind. Of some 109 stomachs of the yellow-billed species that were examined one was found to contain as many as 250 tent caterpillars, probably a whole colony in the young stage, and another 217 fall webworms, and this probably fell far short of the real number as these caterpillars are very small, and in many instances nothing but jaws remained undigested. These birds eat so many hairy caterpillars that the hairs, which are frequently stiff, bristly and sharp, sometimes pierce the inner lining of the stomach and remain there so that when the stomach is opened it is found to be lined with a thin coating of fur.

The cuckoos, despite their fondness for hairy caterpillars, do not by any means confine themselves to these insects but also devour beetles, grasshoppers, sawflies, and bugs of various kinds, most of them of a harmful nature. The cuckoos are extremely useful but unfortunately they are rather shy birds and prefer to remain about the edges of woodlands and groves rather than take to the more open cultivated grounds and orchards although if unmolested they sometimes gain enough confidence to frequent trees about houses and lawns. 

So far I have said nothing of the many birds that are of use to us in helping to get rid of weed seeds. Preeminent among these seed eaters are the sparrows, inobtrusive birds which go about their work of doing away with vast quantities of weed seeds in a very efficient manner. Their work begins even before the seeds are ripe and continues throughout the fall and winter and even far into spring. In late summer the seed-eating habit of these birds is so noticeable as to attract the attention of even a casual observer, for by this time the seeds have ripened and the young sparrows which" have fed on an insectivorous diet are ready to turn to vegetable food. In winter, too, we may find flocks of juncoes and tree sparrows feeding in weedy fields, and it has been estimated that the tree sparrows consume per individual about one-fourth of an ounce a day and in a large agricultural state like Iowa some 875 tons annually. Only a farmer who must free his land from noxious weeds can realize what this vast consumption of weed seeds means in the saving and cost of labor. The above estimate is for a single species only, while, as a matter of fact, there are at least half a dozen species such as the white-crowned sparrow, the white-throated sparrow, the fox sparrow, the song sparrow and several others, that habitually feed during the winter on weed seeds. Some of these birds, moreover, range further south than the tree sparrow and junco so that over the entire country there is, during the colder months, a host of seed eaters at work reducing next year’s crop of useless plants.