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PARASITIC animals are, for the most part, confined to the lower grades of life. Among the Articulates they constitute whole groups; they are less numerous in the Radiates and Mollusca, and when we arrive at the Vertebrata we find very few animals of this nature. As a general rule, the parasitism in these higher types is less complete than in the lower species. Of parasitic birds there are very few examples, North America possessing but a single species, the wellknown Molothrus pecoris, whose history we shall briefly sketch.

The Cow-bird, as it is generally called, is spread over the whole continent, from the Atlantic to the Pacific, and from Mexico to Hudson's Bay. It winters in the Southern States, from Virginia southward into Mexico, frequenting the old corn and rice fields, or gathering in small flocks around the cattle in pastures. About the middle of March it begins to appear in the neighborhood of New York, at first only a few appearing in company with the Red-winged and Crow Blackbirds, but by the end of March or beginning of April, as soon as the spring becomes somewhat settled, they become abundant. They are now seen in numerous small flocks of from five to twenty, of which the females comprise at least two-thirds. These small flocks, or parties, continue in the neighborhood of New York until about the middle or end of June, according to the season, after which time none are seen except, perhaps, a female or two. Towards the early part of September they reappear in numerous flocks of from fifty to five hundred individuals, or even more. They now scatter themselves over the fields, frequenting for the greater part of the time the pastures, where they feed upon the swarms of insects that are constantly to be found in the

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vicinity of herds of cattle. Later in the fall they sometimes associate with the Red-wings, which have now also gathered into flocks. About the middle of October they leave us for the South.

Like the European Cuckoo, the Cow Blackbird lays its eggs in the nests of other birds, never building one for itself. It usually selects the nest of a bird smaller than itself, and never forcibly drives away the rightful owners in order to take possession itself, but waits until they are absent, and then secretly and quickly deposits the egg. Among the birds who are thus victimized are the Red-eyed and White-eyed Vireos, the Maryland Yellow-throat, the Bluebird, Indigo-bird, Chipping and Song Sparrows, Yellow Warbler, Golden-crowned, Wilson's, and Wood Thrushes, Blue-gray Flycatcher, Yellowbird, Towhee Bunting, Black and White Creeper, Purple Finch and Bay-winged Bunting. The favorites are the Maryland Yellow-throat, the summer Yellowbird, and the Vireos.

The egg of the Cow Blackbird is of a dirty white, thickly sprinkled with spots and dashes of reddish brown. Some of these spots are darker than others, and different eggs often show some slight variations in color, as is generally the case, indeed, with all streaked and spotted eggs.

One egg is the most ordinary number in the same nest, but occasionally there are two, one of which, Audubon observes, usually proves addled. I never heard of more than two instances where there were more than two eggs of the Cow-bird in a single nest. Prof. Baird and Dr. Brewer once found three eggs in a nest of the Black and White Creeper, and I once had the good fortune to discover a nest of the same bird containing five eggs of the parasite, together with three of her own. In the latter case, incubation had begun, and all of the eggs contained embryos.

The young Cow Bunting usually breaks the shell a short time before the other occupants of the nest, who, from this circumstance, and the fact that they are smaller and weaker

than their intruding nest-mate, almost always perish. In the latter part of May, and during June, the young Cow-birds may be seen flitting through the woods and orchards; but at this time of the year they do not frequent the open fields as the adult birds do. They do not entirely disappear until July, when most of the small birds have raised their first broods. In September they return in flocks along with the old birds. They do not attain their full plumage until the following spring.

It is not often that the Cow-bird lays her egg in an empty nest, but I have known of one or two instances of the kind. In such cases the owner always, as far as I can learn, deserts her nest. But if, as is almost always the case, she has laid one or two eggs before the parasite has deposited her's, she will generally remain, though often with apparent reluctance. Some birds, however, will often desert their nests even if they have laid in them first, as the Song Sparrow and Wood Thrush. At times some birds show great ingenuity in getting rid of the intruding egg, by building a second floor to the nest, above the egg, thus completely covering it up. The Yellow Warbler, a frequent victim of

a the Bunting, often adopts this method of freeing herself from the annoying parasite; and I have known the Song Sparrow to adopt the same plan. An instance is on record in which a Yellow Warbler, having built a second floor to her nest over an egg of the Cow-bird, found another egg of the same bird laid upon her second story, whereupon she went to work again and built a third floor over the second egg I have known the Cow Bunting to lay her egg on the second story of a nest, but the bird, in this instance, deserted her nest."

The notes of the Cow Blackbird are not many in number, nor musical in tone. When flying, the male utters a whistling sort of note, composed of two syllables. At other times, when perched upon a tree, he utters his love-song, which is composed of two loud preliminary notes, which Nuttall compares to the syllables "gluck tsee,” followed by a medley of low gurgling notes. On a warm morning in April the males will sit upon the tops of the maple and apple trees in the pastures and orchards for an hour at a time, repeating at short intervals their jingling notes, to the intense satisfaction, apparently, of themselves and their numerous mates who sit around them in admiring circles. While uttering these notes the bird struts and swells like a turkey-cock, and with the same intention the desire of pleasing his mates.

The food of the Cow Blackbird consists principally of insects, especially flies, grubs, beetles, etc. They eat also the seeds of various plants, and at times join the Red-winged and Crow Blackbirds in plundering the cornfields; but the injury that they thus inflict is very slight, and is far more than overbalanced by the good they do in devouring vast numbers of noxious insects.' Hence they deserve the protection of the farmer; but as they are often found in suspicious company, viz., with Crows and Red-winged Blackbirds, they frequently suffer the penalty of associating with proscribed thieves and rogues, by being shot down with them.



In May, eight years since, I was attached to a military expedition on its way to the Pacific Coast, via the Missouri and Columbia Rivers, which had just been connected by a military road constructed by Capt. John Mullan, U. S. A. It was chiefly for the purpose of trying its practicability that the party of about two hundred and fifty men and several officers, under the command of Major G. M. Blake, was sent by this new route instead of by the Isthmus of Panama.

Of the two months spent in ascending the Missouri to Fort Benton by steamboat, I will not write very fully, although the tediousness of the trip was enlivened by many interesting scenes, and by observations and collections of numerous specimens of small mammals, birds and eggs. These I packed and directed to the Smithsonian Institution, but they were never received there; the eggs were all collected west of Fort Union. I will briefly enumerate the species for the benefit of future collectors and students of the summer range of our birds. The valley of the Missouri, along that portion, is usually bordered by low trees and shrubbery in the bottom land, while the uplands are quite bare, or only a few stunted trees occur where springs issue from the bluffs.

June 17th, I found the nest and eggs of Empidonax pusillus (probably), on a low tree in a derse dark thicket, built in a sharp crotch; 18th, the nest of the Western Red-tailed Hawk (Buteo montanus), with two eggs partly hatched, on a small oak at a distance from the river; also, two eggs of the Dove (Zenaidura Carolinensis), and one, said to be that of an eagle (?), were brought in by the men. The Wild Pigeon (Ectopistes migratoria) also breeds here. I found the nest and four eggs of the Lark Finch (Chondestes grammaca), situated as usual on the ground, and one of some uncertain sparrow. The next day I obtained that of the Shrike (Collyrio excubitoroides), with six eggs; and one of the Shore Lark (Eremophila cornuta).

A leak having opened in the boiler we were delayed near this place the third day also, and I found it a perfect nursery of birds, the shrubbery on the north bank being full of them and their nests. I obtained there also eight nests of the Redstart (Setophaga ruticilla), with eggs; that of the Chat (Icteria viridis), with four eggs; of the Blackheaded Grosbeak (Guiraca melanocephala); of some small Thrush (Turdus Swainsonii?); of the Cat Bird (Mimus Carolinensis), and two of the Chippy (Spizella socialis). 1

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