ABERT'S TOWHEE 637 



(Coues, 1866); a 'loud chuck" (Coale, 1894); a "hiiit, huit" (Bendire, 

 1890); and a "sharp cMrp" (Brewster, 1882a). The Abert's towhee 

 will occasionally produce a succession of notes which progressively 

 increase in frequency, characterized by Baird, Brewer, and Ridgway 

 (1874b) as "chip, chip, chee-chee-chee." 



Marshall (1960) provides the most comprehensive account of the 

 voice of this species. He characterizes the call note as a "sharp 

 peep," the male song as an "accelerating series of its ordinary call 

 note, peep, often terminating in coarse phrases like the song of a 

 Tolmie Warbler," the locative note as a quavering "seee," the alarm 

 note near a nest A\"ith young as a "tic," and the pair reinforcement 

 call as a "squecd-cha-cha-cha." 



Field marks. — Abert's towhees are light brown birds about 9 inches 

 in total length and weighing approximately 45 grams. The most 

 conspicuous field mark is the black face patch which contrasts sharply 

 with the light-colored conical bill. 



Enemies. — Abert's towhees of both subspecies are occasionally 

 parasitized by cowbu-ds {Molothrus ater obscurus). Brown (1903) 

 found nests with cowbird eggs in them along the Colorado and lower 

 Gila rivers, A. B. Howell found a nest containing a cowbird egg near 

 Gadsden, Yuma County, Ariz. (Friedmann, 1929), andH. Friedmann 

 (1931) records several others near Mesa, Maricopa County, Ariz. 



A number of predators appear to prey on Abert's towhees at all 

 stages in their life history, and Bendire (1890) suggests that snakes, 

 jays, squuTels, hawks, and owls all take a toll of eggs, young, and, 

 in some cases, adults. Gilman (1915) recorded discovering an empty 

 nest with a blacksnake coiled around it near Sacaton, Pinal County, 

 Ariz.; a pair of adult towhees obviously agitated by its presence 

 remained nearby. Roadrunners (Geococcyx calijornicus) may prey 

 on young birds, because one H. C. Bryant (1916) collected at Palo 

 Verde, Imperial County, Calif., contained a nestling Abert's towhee. 

 However, the possibility that the roadrunner had obtained it dead 

 could not be discounted. 



Two helminth parasites have been found in Abert's towhees of the 

 subspecies dumeticolus, collected in the Imperial Valley of California. 

 One of these was a tape worm, Anonchotaenia longiovata (M. Voge and 

 B. S. Davis, 1953); the other, a nemotode crop worm for which 

 the identification is not at this time available (W. R. Dawson, notes). 



Distribution 



Range. — The eastern Abert's towhee (P. a. aberti) is resident along 

 the Gila River and its tributaries in southern Arizona and southwestern 

 New Mexico (Cliff, Redrock). The western Abert's towhee (7^. a. 

 dumeticolus) is resident in the valleys of the Virgin and lower Colorado 



