Yellow-Green Vireo in Arizona, with Notes on Vireo Songs

Abstract

in an area is one or more specimens, something that can be studied in detail by anyone interested at any subsequent date. Trautman and Trautman (1968) have stated this principle very clearly and have based their list of Ohio birds almost entirely on specimens, excluding species based on sight records only. Tape recordings of two birds formed the basis for including Bell's Vireo (Vireo bellii), the only species for which they had no specimens. (Since the Trautmans' paper was published, a specimen of Bell's Vireo has been taken in Ohio. ) Perhaps the Trautmans have set a precedent. In any event, it seems to me that tape recordings-which, like specimens, can be studied in detail by anyone interested at any subsequent date-can provide evidence of a bird's occurrence in an area that is just as valid and authentic as specimens. The purpose of this paper is to document, on the basis of a tape recording, the occurrence in Arizona of a Yellow-green Vireo (Vireo flavoviridis), a species which has not previously been reported from that state (Phillips et al. 1964). On 18 June 1969, while making recordings at a roadside rest area on State Route 82 about 4 mi. SW of Patagonia, Arizona (about 16 mi. NE of Nogales), I obtained a recording of a bird of which I got only a few glimpses, but not a look good enough to identify it by sight. By the time I could play some of its songs back to it in order to bring it into the open, the bird had apparently left the area. The recording was made with a Nagra III B recorder using a tape speed of 15 ips, and with a D-33 American microphone mounted in a 24-inch parabola. This recording is No. 10271 in the tape collection of the Bioacoustics Laboratory, Ohio State University; it is about 4% min in length and contains 162 songs. The singing of this bird was much like that of a Red-eyed Vireo (Vireo olivaceus), but the quality was a little like that of a House Sparrow (Passer domesticus). All I could tell of the bird's appearance was that it was about the size of a large vireo (such as the Red-eyed), and appeared to have some yellow on its underparts. Several people in Arizona who were familiar with the songs of the birds in the Patagonia area were unable to recognize this bird from my recording, and the bird was not found on subsequent visits to this roadside rest area. A copy of this recording was sent to L. Irby Davis, who has recorded several species of vireos in Mexico and Central America; he said (pers. comm.) that it might be a Yellow-green Vireo. The roadside rest area where this recording was made is a narrow area some 150-200 yards long on the southeast side of the road. Southeast of this strip, the land rises abruptly from rocky cliffs at the northeast end to a steep brushy slope at the southwest end. There are numerous trees and shrubs in this rest area, principally sycamore (Platanus Wrightii), walnut (Juglans major), hackberry (Celtis reticulata), mesquite (Prosopis juliflora), catclaw (Acacia Greggii), and elderberry (Sambucus mexicana). Just across the road from the rest area is Sonoita Creek, which has a flow of water and is bordered by similar vegetation, plus willow (Salix Gooddingii), ash (Fraxinus velutina), and cottonwood (Populus Fremontii). The dominant shrub forming the undergrowth in the woods along the stream is Baccharis sp. The elevation here is about 3900 feet. The bird kept to the tops of the larger trees (where it was concealed by the foliage), and ranged over some 50 yards or more of the southwest end of this area.