390 BULLETIN 195, UNITED STATES NATIONAL MUSEUM 



Harry S. Swartli (1929) confirms Mr. Law's diagnosis by say- 

 ing: "Differences between the two lots, east and west of the Santa 

 Ritas, are, in most cases, fairly apparent, especially so in the freshly 

 assumed fall plumage. The eastern birds (eurvirostre) are rather 

 more slaty above, have fairly well marked white wing bars, have 

 sharply defined white tips to the outer rectrices, and the breast spots 

 are large and fairly well defined. The western birds {pahneri) are 

 browner above, lack the wing bars, have the tail spots obscurely indi- 

 cated or else entirely wanting, and have the breast spots less distinct." 



The range of Palmer's thrasher covers a large part of southern 

 and western Arizona, in the Lower Sonoran Zone, north to the cen- 

 tral western part, east to the Santa Rita and Catalina Mountain re- 

 gion, and south to Sonora and northern Chihuahua in Mexico, mostly 

 below 3,000 feet elevation. It is one of the most abundant and char- 

 acteristic birds of these arid plains, where the hard, sun-baked soil 

 supports only a scattered, open growth of small mesquites, grease- 

 wood and creosote bushes, salt bushes and other thorny shrubs, with 

 an occasional ironwood tree, a screwbean, or a paloverde, gorgeous 

 in spring with its solid mass of yellow blossoms. But the most inter- 

 esting features of these desert mesas are the varied forms of cacti 

 that are scattered through this open growth of unattractive, low 

 shrubs that nowhere hide the bare ground. There are several species 

 of choUas, or closely allied forms, of varied shapes and colors with 

 blossoms of different hues, the huge barrel cactus that may someday 

 slake a traveler's thirst, the long, slender stems of the ocotillo with 

 their flaming tips, and, here and there, the picturesque, towering can- 

 delabra of the saguaros punctuate the landscape. Here the Palmer's 

 and Bendire's thrashers find a congenial home, make their nests in the 

 spiny choUas, and vie with the other desert dwellers for the scanty 

 living that such a forbidding region affords. 



But these thrashers are not wholly partial to the open desert mesas ; 

 we frequently saw them about the ranches and often near houses, 

 where they could find a solitary cholla in which to build their nest. 

 Mr. Swarth (1920) says that "about Phoenix and Tempe it is, perhaps, 

 the most abundant single species of bird, and it even ventures into 

 the towns where sheltering brush piles or thickets remain in vacant 

 lots or along roadsides. Cultivated farm lands hold little attraction 

 for the thrasher, however, and it is rarely seen about such places." 



Courtship. — Palmer's thrashers are permanent residents in south- 

 ern Arizona and are probably more or less pennanently mated; at 

 least the pairs seem to remain together during winter. Their court- 

 ship seems to be a very simple affair just preceding nest-building. 

 Earle F. Stafford (1912) has published an interesting account of a 

 pair that spent the winter about his ranch. On February 14, an ap- 

 propriate date, he noticed signs of courtship : "One sidled along the 



