The Condor/24 (6)/Northward Range of the Gray Vireo in California
Northward Range of the Gray Vireo in California. — While on a short collecting trip as guest of Mr. A. Brazier Howell, I spent the afternoon of July 25, 1922, on the west slope of Walker Pass, which is in northeastern Kern County, California, at the southern end of the main high Sierra Nevada. The feature of the occasion was my meeting with an adult pair of Gray Vireos (Vireo vicinor). The exact spot was on a steep, north-facing hillside within one-fourth mile south of "Jack's Station" (now merely a roadside camping place); altitude close to 4500 feet; life-zone Upper Sonoran, in a semi-arid phase of it. The birds were in sparse brush (Garrya, Kunzia, Artemisia tridentata, and Cercocarpus betulaefolius); and a digger pine and a pinyon both grew within one hundred feet of where they were discovered.
I was first attracted by the broken, post-nuptially rendered song of the male — intermittent and sketchy, yet distinct enough from the songs of other vireos to be recognized at once. This male Gray Vireo was promptly shot. It proved to be in molt, with only two of the old tall-feathers remaining and with new feathers showing where old ones had fallen out, in the wings and in most of the body tracts. The weight of the bird was 12.5 grams. It is now catalogued as no. 43295 of the bird collection in the California Museum of Vertebrate Zoology.
A minute or two after shooting the singing bird, I caught sight of the other bird which I concluded was the female of the pair. The only note she gave was a low harsh churr or shray, given now and then as she hopped slowly through the twiggery. From the bushes she went into the pinyon tree before mentioned, and thence into the digger pine, reaching the unusual height of some fifteen feet above the slope at the base of the tree. Her head was turned from side to side at frequent intervals, especially when she approached and eyed me curiously at a range of not more than twelve feet.
As for field characters, besides the general deliberateness of movement, the thick, dark-colored bill was well seen; the gray tone of color both above and below was noticeable; there was no crest, nor inclination to a crest. I was particularly struck by the relative great length of tail, for a vireo; also this member drooped, most of the time, below the axis-line of the body. It will be recalled that chaparral-dwellers in general, whatever their genetic affiliations, have relatively long tails — for example, Bell Sparrows, Bewick Wrens, Wren-tits, Gnatcatchers, Towhees, and Thrashers.
Some of the above observations will be found new or supplementary to those reported for the Gray Vireo from the San Jacinto region (Grinnell and Swarth, Univ. Calif. Publ. Zool., vol. 10, 1913, pp. 291-297).
This Walker Pass record is the northernmost in California so far known for the species. In fact, only one other occurrence has been reported from north of west-central Los Angeles County (whence reported by Loye Miller, Condor, xxii, 1921, p. 194). This other northern record (Grinnell, Pac. Coast Avifauna no. 11, 1915, p. 144) is for a point at 2400 feet altitude near Bodfish, on the Kern River, in Kern County. An adult female (now no. 20679, Mus. Vert. Zool.) was collected there by Waiter P. Taylor on June 16, 1911. It is in worn "breeding" plumage. Mr. Taylor's field-notes indicate that the bird was taken on a slope clothed in part with junipers and digger pines — evidently good Upper Sonoran. The date of capture would argue for its nesting in the immediate vicinity.
There are vast areas of the same sort of territory as has afforded the two Kern County records, around the southern Sierra Nevada. It all looks like perfectly proper country for Gray Vireos. I am tempted to believe that the species will be found widely, though not abundantly, represented there by someone seeking it in May or June, who is familiar with its song and habitat predilections. — J. Grinnell, Museum of Vertebrate Zoology, University of Calilornia, Berkeley, August 19, 1922.