The Birds of Rock Canyon, Arizona 73 



Wilsonia p. pileolata — Pileolated Warbler. Not uncommon at 

 camp for a few days during the latter part of May. 



Mimus p. leucopterus — Western Mockingbird. Not uncommon; 

 usually found in the desert. Only occasionally heard singing. 



Toxostonia c. palmeri — Palmer's Thrasher. Abundant. By far 

 the most numerous bird and one of the few found any distance 

 from the water-courses in the desert. One brood of young had 

 already been raised and many nests were found containing eggs 

 and young in all stages of development. Their call-note may be 

 readily adapted to the phrase " Pretty quick," with the accent on 

 the " quick." 



Nests were usually placed in the chollas, but some were found 

 in the mesquites and palo verdes. 



CatTierpes m. conspersiis — Canyon Wren. Rare. Heard on one or 

 two occasions in the canyon above camp. 



Heleodytes ft. conesi — Cactus Wren. Plentiful. The most char- 

 acteristic bird of the cactus desert. They also had raised one 

 brood and were engaged in caring for the second at the time of 

 our visit. A few sets of eggs (both fresh and incubated) were 

 also found. Nest almost invariably placed in a cholla; only one 

 found not so placed, and that in a palo verde. 



Aiiriparus f. flaviceps — Verdin. Not uncommon, and their retort- 

 shaped nests were found in numbers, though usually unoccupied. 

 We succeeded, however, in securing two sets of young just ready to 

 leave the nest. Their plumage was much frayed out, but when 

 one considers the combing that the feathers of many of these des- 

 ert birds are subjected to it, it is more surprising that they retain 

 any body covering at all. Nevertheless, we found very few spines 

 in birds' feet, and saw absolutely no evidence that would lead us 

 to believe more serious tragedies of common occurrence. 



Polioptila plumhea — Plumbeous Gnatcatcher. Plentiful. Adults 

 and fully grown young found everywhere. Most abundant in the 

 dry water-courses near the main stream. 



Hylocichla u. ustulata — Russet-backed Thrush. Not common. 

 (Rare)? For a few days during the latter part of May thrushes 

 were not uncommon, and I took one on the 24th, thinking it to be 

 ti. swainsoni, but upon comparing it with California specimens of 

 true ustulata at the Museum, I am satisfied it should be so referred, 

 though I cannot, of course, state positively that all Hylocichla seen 

 were of the same variety, and it is quite possible that a large series 

 would have contained both forms in more or less equal numbers. 



