1914 



BIRDS OF ARIZONA 



89 



Most of these are migratory species which spend the summer at varying dis- 

 tances directly to the northward, and it 'is to he expected, of course, that they 

 should occur in winter in this state. The occurrence of Jkiico o. thurberi and 

 Hylocichla g. nanus is further evidence of the existence of a migration route 

 across the deserts to the westward, as shown by the various Pacific Coast birds mi- 

 grating through Arizona. 



Transient Species 



Empidonax griseus 



Spizella pallida 



Passerina ciris 



Spiza americana 



Iridoprocne bicolor 



Lanivireo solitarius cassmi 



Vermivora rubricapilla gutturalis 



Vermivora celata lutescens 



Dendroica aestiva brewsteri 



Dendroica townsendi 



Dendroica occidentalis 



Seiurus noveboracensis notabilis 



Wilsonia pusilla chryseola 



Hylocichla ustulata ustulata 



Hylocichla guttata slevini 



The thirty species listed above occur, as far as we know, merely as migrants, 

 passing through Arizona on their way to and from their breeding grounds, 

 neither nesting nor wintering anywhere within the state. Twelve of these species 

 spend the summer on the Pacific coast in California or farther north, and their 

 abundance during the migrations indicates the presence of a well defined migra- 

 tion route from southeast Arizona almost due westward and across the inter- 

 vening deserts. These species are: Chaetura vauxi, Selasphorus rufus, Stellula 

 calliope, Empidonax hammondi, Lanivireo s. eassini, Vermivora r. gutturalis. 

 Vermivora c. lutescens, Dendroica townsendi. Dendroica occidentalis. Wilsonia 

 p. chryseola, Hylocichla it. ustulata, and Hylocichla g. slevini. 



Five of the species listed breed in the far north, and pass through Arizona 

 in the course of a direct north and south migration. These are: Pisobia bairdi, 

 Totanus melanoleucus. Helodromas s. cinnamomeus, Aegialitis semipalmata, 

 Seiurus n. notabilis. Four other species breeding at nearer points north of 

 Arizona, and hence following the same migration route through the state, are: 

 Steganopus tricolor, Himantopus mexicanus, Numenius americanus. Dendroica 

 a. brewsteri. 



Spizella pallida, Passerina ciris, and Spiza americana are species from 

 regions east of Arizona whose manner of occurrence, usually in the late summer, 

 is apparently indicative of established migration routes. Of the remaining six 

 species on the list of migrants, Herodias egretta. Egretta c. candidissima, Pandion 

 h. carolinensis, Empidonax wrighti. Empidonax griseus, and Iridoprocne bicolor, 

 it may be that some or all will be found breeding within the state, but the 

 data available at the present time shows their presence only during the period of 

 migration. 



