TURKEY VULTURE. Cathartes aura septentrionalis Wied

Field characters.—General appearance that of "bird of prey;" size large, about that of Red-tailed Hawk; plumage black, with faintly gray area on lower surface of wing (pl. 44e); head red, nearly naked. Voice: A low hiss, rarely uttered. Usually seen soaring overhead in wide circles, with wings slanting upward. When perched, sits in a hunched-up posture, with head drawn in between shoulders.

Occurrence.—Common in summer on west slope of Sierra Nevada, in both Lower and Upper Sonoran zones. Easternmost point of regular observation, 3 miles east of Coulterville, at 3200 feet altitude. Twice noted over Yosemite Valley in summer of 1920 (C. W. Michael, MS).

As a rule, most large birds of the Yosemite section are so uncommon that to observe one of them is a notable occurrence. The Turkey Vulture, or Buzzard as it is called locally, is, within its range, a conspicuous exception. All over the western country below the Transition Zone, it is common and present throughout the greater portion of the year.

In bulk the Turkey Buzzard about equals the Red-tailed Hawk; it is of only about one-third the weight of the Golden Eagle. Its black plumage, and the grayish patch on the under surface of each wing, make it easy to distinguish from all our other birds of prey. In flight the tips of the outermost five or six primary flight feathers are distinctly separated like the spread fingers on a person's hand (pl. 44e), but the tail is held closed so that, seen from below, it has a narrow, wedge-shaped outline. The Turkey Buzzard spends a very large share of its time on the wing, sailing about in almost unceasing watch for food. When soaring, the buzzard usually holds its wings bent upward, so that a more or less distinct angle, with the apex downwards, is formed between them. Often a bird will soar in circles for several minutes at a time without appearing to alter the position of a single feather, accommodation to differences in the air currents seemingly being made by movement of the body as a whole. As the bird glides down over the brush of a cañon side, it often careens from side to side, but without changing the relative positions of wings or tail.

These big birds distribute themselves over their range with remarkable uniformity. Probably the average population is but one or two individuals to the square mile. Each seems to be scrutinizing a definite area; if one bird discovers any large item of food the others quickly take notice. As the original discoverer of the food with obviously increased animation drops down onto his find, his nearest neighbors cease their patrolling and close in toward the place where he descended. In turn the birds beyond them close in and so on until, if the object be a large one, such as the carcass of a horse or cow, as many as thirty or forty will finally congregate at the one spot.

The buzzards' inspection of the country over which they range is exceedingly minute, and rarely does even so small an object as the body of a ground squirrel escape their detection. In fact, bodies of small birds and even of mice, used as bait for traps and placed under shelter of bushes, are often detected by the buzzards. Much of this keenness is in their eyesight; they seem to depend but little, primarily, upon the sense of smell, although this latter sense may also be highly developed as an auxiliary faculty in locating food.

The flight of the Turkey Buzzard in migration is an impressive sight. At Pleasant Valley on the afternoon of February 26, 1916, about 75 were seen manoeuvering about over a hill to the west, and at the moment their general movement was toward the south. Half an hour later, the flock was again seen, from the Baxter road. They were then in an elongated formation and sailing rather low. A few seconds later the leaders turned and soon all members of the flock were circling about, each one weaving its course in and out between its companions, much in the manner of participants in a Maypole dance. All the while this circling continued the birds were rising higher and higher. Finally, having probably attained an altitude which gave unobstructed view up and down the foothills, the flock, with surprising concert, again assumed the elongated formation, with usually not more than four nearly abreast, and quickly passed northeastward over the hills and out of sight. While circling, and even when moving forward, the birds engaged in a relatively small amount of flapping; usually they would sail for a half-minute or more without perceptible change in the posture of body, wings, or tail. After the flock had passed on, a single bird was seen circling in the place where its companions had lately been and three other birds sailed slowly about over the opposite wall of the Merced Cañon. Residents said that these birds were the first for that season. Next day the newly arrived individuals behaved as though perfectly at home, and had their coming not been witnessed on the previous day there would have been no reason to believe that they had been there only overnight. Evidently no time is lost in settling down.

In the early morning hours just before or just after sunrise, buzzards perch in hunched-up postures, on trees by the roadside. Often four or more birds may be observed in a single tree, evidently waiting until the air conditions become such as to enable them to soar about in their accustomed manner. When approached, these birds often spread their wings and hold them extended for several minutes, and sometimes they successively expand and fold these members several times before jumping into the air. Only a few strokes of the wings are used when starting. Often the birds' positions will enable them to strike down a cañon so as to gain the necessary initial momentum, and they then slowly rise by repeated circlings with few or no further wing strokes.

Residents say that in the spring Turkey Buzzards appear with the advent of good weather and vanish temporarily during storms. Possibly they repair to tree perches in remote ravines, or to the shelter of the caves on the adjacent rocky hillsides where they are known to nest during the summer months.

Near Hayward (an old roadhouse on the road between Lagrange and Coulterville), a partially albino Turkey Buzzard was seen in flight on May 9, 1919. The back and upper surface of the wings were almost solidly white, but the remainder of the plumage, as seen with the binoculars, appeared to be of normal color. This is just another instance in the seemingly endless series in which albinism makes its appearance. Albinos always excite great curiosity, perhaps more than they really deserve.