Читать книгу Life Histories of North American Jays, Crows, and Titmice - Arthur Cleveland Bent - Страница 46

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Belding’s jay now seems to be recognized as a valid race of the coerulescens species, inhabiting northwestern Baja California as far south as latitude 30° N. It was named by A. W. Anthony (1889) and described as “differing from A. californica in much darker colors and weaker feet.” It was accepted by the A. O. U. committee in the 1910 and the 1931 Check-lists, and by Ridgway (1904), regardless of the fact that it is practically identical in coloration and size with the California jays found in the southern half of the coast region of California, though darker and smaller than the long-tailed jay (immanis) found in the interior of California, as shown by Swarth (1918). Mr. Swarth’s remarks on the subject are worth quoting in full, as they throw some light on the status of this race. In his study of this genus, he says:

The present treatment of the races of the California jay differs from that in most recent literature covering the subject (e.g., A. O. U. Check-list, 1910, p. 225; Ridgway, 1904, pp. 327-331) in that it does not recognize the subspecies obscura. This race was described by Anthony (1889, p. 75) from specimens taken in the San Pedro Martir Mountains, Lower California. In a subsequent paper (1893, p. 239) the same writer asserts that birds from the San Pedro Martir Mountains and from San Diego County, California, are indistinguishable, and for some years past the name obscura has been generally used to cover the bird of the San Diegan region of California. * * * Comparison of series from these points, however, with specimens from various coastal localities as far north as San Francisco Bay (including the vicinity of Monterey, the type locality of californica), shows that all belong to the same race, that there are no characters serving to distinguish specimens from these several places. Hence the name obscura must be considered a synonym of californica.

Aphelocoma californica obscura was described as a smaller and darker colored bird than A. c. californica. Perpetuation of this error may have occurred through comparison of southern California specimens with others from the Sacramento Valley or the Sierra Nevada, in the belief that the latter were representative of typical californica. This assumption is wrong, however, and although jays from certain sections of California may readily be distinguished as, respectively, larger and paler, or smaller and darker, true californica and obscura both fall into the latter category.

It is significant, also, that Mr. Anthony (1893), in his subsequent paper, appears in doubt about the status of this race, for he says; “It seems, however, from the series now on hand as if obscura would have to be reduced to a synonym of californica.”

The San Pedro Mártir Mountains have produced so many new subspecies, five described by Mr. Anthony (1889) and a number more by others, that it seems worth while to quote his description of them:

About one hundred and fifty miles south of the United States boundary, and midway between the Pacific Ocean and Gulf of California, lies a high range of mountains, which is marked upon the later maps of the peninsula as ‘San Pedro Martir.’ The region embraces a series of small ranges which rise from an elevated mesa, having a mean elevation of about 8,000 feet, and an extent of sixty by twenty miles. In these mountains are born the only streams that this part of the peninsula affords, and an abundance of pine timber is found throughout the region. Many of the ranges on the eastern side of the San Pedro Martir rise to an elevation of 11,000 feet, or even, in one or two places, to 12,000 (?) feet.

Arising as the region does from the dry, barren hills of the lower country to an elevation higher than any other on the peninsula or in Southern California, and presenting in its alpine vegetation and clear mountain streams features so different from the dry manzanita and sage-covered hills of the surrounding country, it is not unnatural to suppose that its animal life would be found to differ in some respects from that of the surrounding hills.

Mr. Anthony found this jay ranging up to 10,000 feet in these mountains. He says nothing about the habits of the bird, and nothing seems to be published on the subject elsewhere.

The measurements of 12 eggs average 27.8 by 20.8 millimeters; the eggs showing the four extremes measure 29.2 by 21.1, 26.4 by 20.6, and 26.8 by 20.2 millimeters.