WESTERN HOUSE WREN. Troglodytes aëdon parkmani (Audubon)

Field characters.—Much smaller than Junco; more nearly size of Kinglet; bill slender, nearly straight. General coloration dull brown, paler on under surface. No contrasted markings of any sort. (See pl. 54.) Very active and talkative. Voice: Song of male a rapidly delivered series of bubbling notes; song repeated at frequent intervals; call note harsh and scolding.

Occurrence.—Common summer visitant to Upper Sonoran Zone on west slope and to Transition Zone on east side of Sierra Nevada. Recorded from Pleasant Valley eastward to El Portal and also about Mono Lake. After nesting season many immature individuals invade higher altitudes, as at Glacier Point (August 17), Merced Lake (August 21), Washburn Lake (August 24), and head of Lyell Cañon at 9200 feet (July 23, all dates in 1915). A few individuals winter in western part of region as at El Portal (December 4, 1914) and Snelling (January 2 and 6, 1915). Lives near ground (usually below 10 feet), chiefly about deciduous trees. Solitary or in pairs.

The Western House Wren or Parkman Wren is a common and conspicuous element in the summer bird life in the oak belt of the western foothill country. It is present also in small numbers from May until September east of the Sierras. Were these two separated areas the only territory visited by the birds, the species would not often come to the attention of the Yosemite traveler. But in the late summer and early fall months the young wrens which have been reared in the Upper Sonoran and Transition zones invade the higher levels, even to the Hudsonian Zone, and continue there for some weeks before departing southward.

The Western House Wren arrives within its nesting range on the west slope of the mountains rather early in the season. The species was found to be already well established at El Portal upon our visit to that place on April 27, 1916. East of the Sierras it was not noticed until May 9 (1916). The latest fall record on the west slope above the Upper Sonoran Zone is for September 15 (1917), in Yosemite Valley (Mailliard, 1918, p. 19); while one of our party saw an individual bird on the east slope near Williams Butte on September 22, 1915. In Yosemite Valley the House Wren appeared in 1920 on July 30, and thereafter the species was noted on August 18 and 27 and on September 4 and 6 and 26 to 28, in the same year (C. W. Michael, MS).

Of the wrens found in the Yosemite region the House Wren is next to the smallest in size. Its coloration is plain brown, only slightly paler below than above, and the bird has no white line over the eye or other contrasted markings of any sort. (See pl. 54.) The Winter Wren is more chunkily built, with a much shorter tail, and warmer tone of coloration; and the San Joaquin (Bewick) Wren is larger, more whitish beneath, and has a white stripe over the eye. The Cañon and Rock wrens are enough larger as not to be confused with the House Wren.

Few birds sing more persistently during a brief period in the spring than the Western House Wren. The song is a series of burred warbling notes, uttered so fast as to defy imitation, and is repeated at frequent intervals. One individual studied at El Portal on April 27, 1916, was giving songs each of which lasted from 2 to 3 seconds, and a new song was commenced every 4 to 6 seconds. The general pitch of each song is about the same throughout, but the intensity weakens at the end. There are none of the clear notes heard in the song of the San Joaquin Wren. When singing, the male House Wren usually perches well above the ground, but still considerably beneath the crown-foliage of the tree in which it happens to be. The song perch is usually situated within a few feet of the nest site. The call note is a rather harsh scold, sometimes repeated rapidly several times.

The name House Wren implies, correctly, that this bird (and more especially the eastern race) has, with the advent of civilization, taken to nesting about dwellings. Throughout its range the species is noted for making use of any cavity, natural or artificial, which is suited to its needs with respect to size of entrance hole and to interior dimensions.

On the east side of the mountains, in 1916, Mr. Dixon found 3 nests of this wren. The first, discovered on June 2, at about 7300 feet altitude near Williams Butte, was in an old nest hole of the Red-shafted Flicker 3 feet above the ground in a dead aspen. (See pl. 54a). On this date the birds were carrying nest material in the form of small sticks. Trips were being made about 7 minutes apart. The individual which did the singing carried most of the sticks, and it often scolded and chased the mate when the latter ventured to look into the nest hole. On June 23, a nest was observed in an old one-quart oil can which was hanging inside a building. (See pl. 54b). The entrance hole of the can was barely large enough (exactly one inch in diameter), for a parent to pass through. Both adults were bringing food for the six young birds which the nest contained. On June 26 a third nest was found in a natural cavity in an aspen growing near Parker Creek, at an altitude of 7500 feet. There were 7 eggs in this nest.