1910] 



Tracy: White Markings in Birds. 



301 



FBINGILLIDAE 



Pyrrhula cassini 

 Carpodacus purpureus 

 Carpodacus cassini 

 Carpodacus mexicanus frontalis, 



and other subsp. 

 Carpodacus amplus 

 Loxia curvirostra 

 Acanthis linaria 

 Acanthis hornemanni 

 Spinus pinus 

 Astragalinus lawrencei 

 Cardinalis cardinalis 

 Melospiza melodia 

 Melospiza georgiana 

 Melospiza lincolni 

 Zonotrichia albicollis 

 Zonotrichia leucophrys 

 Zonotrichia coronata 

 Zonotrichia querula 

 Passerella iliaca 

 Empidonax difficilis 

 Empidonax flaviventris 

 Empidonax trailli 

 Empidonax minimus 



Empidonax hammondi 

 Empidonax wrighti 

 Empidonax virescens 

 Empidonax griseus 

 Empidonax fulvifrons 

 Pyrocephalus rubineus 

 canus 



Camptostoma imberbe 



HlRUNDINIDAE 



Progne chalybea 

 Progne subis 

 Progne cryptoleuca 

 Iridoprocne bicolor 

 Riparia riparia 



BOMBYCILLIDAE 



Bombycilla cedrorum 



VlEEONIDAE 



Vireosylva olivacea 

 Vireosylva philadelphica 

 Vireosylva gilva 

 Lanivireo flavifrons 

 Vireo atricapillus 

 Vireo griseus 

 Vireo vicinior 



mexi- 



The facts as to the distribution of white markings among 

 birds of the various local associations may be gathered from a 

 study of the first list. It also affords a basis for finding any 

 agreement of physical or temperamental characters among birds 

 so marked, or the occurrence of habits that may have a bearing on 

 their coloration. A similar purpose is served by the second list 

 with this drawback : it includes a number of color features that 

 may be of a value similar to that of white patterns, and even 

 more revealing. Accordingly we need not be surprised if we 

 find among species bearing such features, for example, nearly all 

 the crows and blackbirds, the habits" and distribution that 

 are characteristic of white-marked birds. 



There is, moreover, a correspondence, especially among the 

 unmarked groups, that appears to be due primarily to intrinsic 

 influences producing family characters; like all color characters 

 these are too inconstant for the systematist to utilize. Still, in 

 some cases they suggest a persistence of some ancestral type 

 dominating extrinsic influences. Such a correspondence is seen 



