Animal Life in the Yosemite
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THE BIRDS

WRIGHT FLYCATCHER. Empidonax wrighti Baird

Field characters.—Smaller than Junco. No striking white or bright markings anywhere. Whole bird appearing dark grayish brown; color tone on under surface of body yellowish gray; outer surface of closed wing crossed by two light bars; narrow ring around eye, dull whitish, this giving the bird a wide-eyed expression; lower mandible dusky, not yellowish. Perches with drooping wings and tail on prominent twig tips whence it flits out after insects which fly past. Voice: Call note pit, or swee'pit, sometimes a louder ter, terwhit'; song a varied series of lisping notes, see'pit, wurt'zel, see'pit, swer'zel, see'wurz, etc.

Occurrence.—Common summer visitant to Upper Transition, Canadian, and (less commonly) Hudsonian zones on both slopes of Sierra Nevada. Recorded from Hazel Green and Chinquapin east to Mono Lake Post Office. Highest station, head of Lyell Cañon, 9600 feet (July 19, 1915). Present on floor of Yosemite Valley, at least in spring. Noted during spring migration at Dudley, April 29, 1916 (D. D. McLean coll.), and at Pleasant Valley, May 24, 1915. Inhabits brush patches, foraging and singing from perches above these and less often from limbs 10 to 30 feet above ground in adjacent trees.

The Wright Flycatcher is one of a group of small flycatchers (genus Empidonax), the members of which are so closely similar in size and coloration that they cannot always be distinguished from one another in life on these characters alone, even by an expert. Fortunately, some of the species in this assemblage possess distinctive call notes by which they may be recognized; and each of them occupies a particular habitat or type of country, so that as a rule they may be identified upon the basis of these life characteristics with a fair degree of certainty. Thus the Wright Flycatcher is characterized by the lisping quality of its rather protracted song (described in detail farther on), and by its preference for the chaparral slopes of the higher altitudes (mostly above 6000 feet).

The earliest seasonal record we made for the Wright Flycatcher in the Yosemite region is for April 29, 1916, when an adult male was collected near Williams Butte, east of the mountains. When we arrived at Hazel Green, on May 14, 1919, these flycatchers were already present; by May 17, in the same year, males had established posts in Yosemite Valley, and by May 19, at Chinquapin. The species probably arrives in the Yosemite region in numbers during late April or early May. Through the summer it is common within its proper range, which extends to greater altitudes than that of any of the other members of the group. After the young are reared the birds indulge in a slight up-mountain movement to still higher levels, even to timber line, in an endeavor to profit by the increased food supply then available there. The latest record of this bird at hand is for September 13, 1915, when 5 were seen and 2 collected for positive identification, at Gem Lake (altitude 9036 feet). The 5 birds were in willows, a habitat not usually frequented by the Wright Flycatcher during the summer season. This of course marked them as transients; for it is well known that many species of birds during migration forage or seek shelter in situations totally different from those which they customarily occupy during the nesting season.

At Chinquapin, on May 21, 1919, a pair of Wright Flycatchers was found exercising squatter's rights over about an acre of dense chaparral on a flat near the stage barns. The thicket was about four feet high and comprised a dense growth of snowbush (Ceanothus cordulatus), green manzanita, and chinquapin. The male bird had a number of forage posts at the tops of some dwarfed black oaks which struggled up slightly above the general level of the chaparral; he would progress from one to another of these in rather regular succession, catching flies en route. Occasionally he would go up higher, 30 feet or so, to one of the outstanding limbs of a neighboring sugar pine or red fir, and from there he would sing. The female did not seek such prominent perches but kept flying low between the clumps of brush, often disappearing completely within a canopy of top-foliage, but as far as could be determined at no particular spot. No nest was located and it is likely that building did not commence until some days later. At the same locality on June 10, 1915, a bird of this species was seen carrying nesting material into a similar thicket. Fly catchers generally nest somewhat later than vegetarian birds, probably because flying insects, especially in the mountains, do not become abundant enough to ensure successfully rearing a broad of young until the season is considerably advanced. As one goes up the mountains to higher zones, 'spring' and 'summer' are observed to occur later and later according to the calendar.

A male Wright Flycatcher which came to our attention on the floor of Yosemite Valley near Stoneman bridge had evidently located there for the summer. His singing perch was a limb of a yellow pine about 30 feet above the ground; below him were numerous chokecherry thickets. No female was seen. The bird was watched on several occasions between May 19 and 22, and his song translated on the spot as follows: se-put, wurt'sel, see'-pit, swer'-zel, see'wurz, and so on. Another translation was simpler, p-sip', reck, p-slip, or even, be-sick', wreck, be-sick'. There was a lisping quality to the utterance throughout, as indicated by the number of sibilants. Each phrase of the song was accompanied by a violent tweak of the head and a synchronized jerk of the tail, and at the time of utterance the wing tips were dropped below and apart from the small and slender tail. The intervals between songs varied in length and during these rests the flycatcher would occasionally launch forth after a passing insect.

The song of the Wright Flycatcher appears to be more extensive and more varied than that of any of the other small flycatchers occurring on the west side of the mountains. Even so, it is relatively simple as compared with the songs of many of the other woodland birds. These fly catchers (the family Tyrannidae) are not true song birds, their vocal muscles being fewer in number and less developed than those of the sparrows, warblers, and thrushes. The call note of the Wright Flycatcher is see'pit, or simply pit, and is repeated at short intervals. Occasionally a throaty serz is interpolated. And the combination of these, in variable series, constitutes the song. When the birds are down in the brush the soft pit is the note most given. Presumably this is the call note exchanged by two birds of a pair so that each may keep track of the whereabouts of the other.



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Animal Life in the Yosemite
©1924, University of California Press
Museum of Vertebrate Zoology

grinnell/birds90.htm — 19-Jan-2006