BAND-TAILED PIGEON. Columba fasciata fasciata Say

Field characters.—Size and proportions of domestic pigeon; general effect of coloration of upper surface bluish gray, of under surface pinkish brown; a distinct dark band across middle of square-ended tail. (See pl. 4.) Flight swift and direct, with steadily flapping wings; leaves perch with a loud clapping of wings. Voice: A deep, rolled, coo'-coo, or too-coo', resembling that of a domestic pigeon.

Occurrence.—Common summer visitant to Transition Zone on west slope of Sierra Nevada. During winter season, ranges down through Upper Sonoran Zone, following food supply as available. Observed in Yosemite Valley at almost all times of the year. Usually encountered in small flocks in open forests near or in oak trees or berry producing shrubs.

A visit to the Yosemite offers to the naturalist, among other attractions, an exceptional opportunity to study Band-tailed Pigeons. These handsome birds (pl. 4) are likely to be found in the Valley in some numbers at almost all times of the year. They are commonest in spring and fall; flocks of from ten to a hundred were noted by us almost daily in those seasons. But they were present, also, all summer, though in lesser numbers, and during winter as well, save when heavy snow covered the trees and the ground.

Band-tailed Pigeons have the flocking habit strongly developed. To be sure, they scatter out when nesting; but even during this period, when not actually engaged in caring for eggs or squabs, the parent birds assemble in small flocks for feeding. The gregarious habit of the pigeons probably serves them usefully in two ways: a larger measure of protection from enemies is secured through the increased vigilance possible with many pairs of eyes; and, by the same means, a better chance of finding adequate food supplies is provided. The individual bird, and hence the species, profits by a certain degree of cooperation. The flocks are loosely constituted, and when disturbed while foraging the individuals flush scatteringly. At times small companies leave the main flock to seek safety independently.

Often as we ascended the steep trails which lead out of the Yosemite Valley we would come upon Band-tailed Pigeons sunning and preening themselves on the exposed upper branches of the oaks or cedar trees which cling to the cañon walls. Once we noted a group of eight contentedly drinking and preening on a flat rock bordering the rushing waters above Vernal Falls. While some of the birds were thus enjoying repose, others in the neighborhood were to be found seeking acorns in the densely foliaged golden oaks bordering the trails. At times, a bird which was perched high on the Valley wall, would take flight and precipitate itself into the cañon below, going at lightning speed, with wings set almost at its sides, and body veering slightly from side to side. The sense of the vast depth below was intensified by this downward rush, for although it was made too swiftly to permit the eye to focus upon the bird as it flashed by, yet the pigeon remained in view for some seconds before it reached the vanishing point in its downward course.

One would surmise from the relatively large size of these pigeons that they would be conspicuous when perched in open trees such as black oaks; but such is not the case. It often happens that the first intimation of the presence of a flock of pigeons comes when one or more leave precipitately on loudly clapping wings and make off in direct course to some other perch. The birds get under way with surprising rapidity, due to the forceful jump by which they launch into the air and also to the initial strokes of their wide-sweeping wings. A small flock perched in the top of a dead pine was seen to leave with such force that several of the dry weathered branches were broken by the vigorous jumps of the birds. The crashing of the falling branches and the clapping of the pigeons' wings made a vivid impression upon the observer. When a flock of pigeons is engaged in foraging, a person can often hear them at a considerable distance, for the birds flap noisily as they change their positions or seek to balance their heavy bodies on the slender twigs.

The manner of foraging and of eluding approach in the open is well illustrated by the behavior of a large flock watched on the floor of Yosemite Valley near Indian Creek on the afternoon of April 28, 1916. Our note-book record reads:

At the edge of a newly planted grain field where tree shelter was near, fully a hundred of the big blue birds were feeding on the ground. They moved forward as a flock, several feet a minute, those in the rear continually flying up and beyond those at the front. At my distant approach they all flew up into the adjacent yellow pines and cottonwoods; the flapping of their wings as they arose produced a surprising amount of noise, and as they alighted the ends of their fan-shaped, spread tails gave the effect of a scattered series of white crescents against the dark green trees. The birds continued wary and as I came under their perches they flushed in small parties or singly and flew to another clump of trees some distance away. From there, as I followed, they made off in one large band and three smaller ones, circling widely out over the field. As they left, the only color impression I got was of dark blue, but later, when outlined in flight against the sky, the pinkish blush of their breasts was clearly seen.

A few days later, opportunity was afforded to observe at closer range a small flock in the dooryard of a home among the black oaks on the north side of the Valley (pl. 43a).

As the big birds alighted, the air currents caused by their wings and tails stirred up the dust and chaff of the yard to form small whirlwinds. When feeding, the birds walked about actively, their big bodies swinging from side to side as they stretched their short legs in endeavoring to move quickly. Usually the head was held so low that the back of the neck and body and tail were in one plane parallel to the ground, and they would look up only when some moving object or unusual sound prompted them to be on guard. Otherwise they pecked greedily at the abundant supply of grain scattered about. One bird seemed exceptionally thick-breasted, as though it had a very full crop. When in the trees a few of the birds uttered a mild tuck-oo', not spirited; but as a rule they were silent. When disturbed they arose abruptly, almost simultaneously, with a great clapping of wings, displaying spread tails. When descending to the ground they often made two or three short flights, from one elevation to another lower one, rather than one direct descent.

Mr. Gabriel Souvelewsky told us that once when blasting was being carried on in the Valley a flock of Band-tailed Pigeons feeding on the ground in his yard would rise 3 or 4 feet at each blast and then drop back again quickly as their alarm subsided.

We did not succeed in locating any nests of the Band-tailed Pigeon. Nests in other parts of California have been found in airy situations, for example, on large horizontal limbs of trees where the birds could flush directly at the approach of danger. It yet remains for someone to observe and report an instance of nesting in the Yosemite region. The continued presence of pigeons in the Valley throughout the summer months makes it almost certain that they nest there.

Acorns form the main item in the food of the Band-tailed Pigeon. We often saw birds foraging in the golden oaks on the north wall of the Yosemite, and several birds collected there were found to have nothing but acorns in their crops. A resident of Mount Bullion told us that he had shot a pigeon near that place whose crop contained 13 acorns of the black oak. Other common food materials include berries of the manzanita, toyon, chokeberry and coffeeberry. Grain, when available, affords attractive forage; they eagerly glean shelled-out kernels. This last trait works to their disadvantage in those cases where strychnine-poisoned grain has been put out on top of the ground to kill ground squirrels. On several occasions grain so exposed in the Valley has been eaten by the pigeons and some of the birds are known to have succumbed.

People who have resided for a long time in Yosemite Valley state that pigeons used to be found there in much larger numbers than now. Mr. C. W. Baker said that fully 2000 were observed by him in one flock some years previous to 1915. Excessive hunting in the foothill belt during the winter months has probably been the direct cause of most of this decrease. The pigeon is not a species that can recover rapidly from serious reduction, for normally only one young bird is reared by each pair each year. Variation in the available supply of food there and elsewhere probably has also had a marked effect on the number of pigeons visiting the Yosemite Valley from year to year. Fluctuations for such reasons make it difficult to determine with accuracy to what extent the birds have actually been reduced in numbers in the region.