1910] 



Tracy : White Markings in Birds. 



305 



SPECIAL STUDY OF THE MNIOTILTIDAE 



For a more minute study of the relation of white color marks 

 to a bird's habitual range I have chosen the American wood 

 warblers. Not only are the members of this family very well 

 distributed among the more or less well defined strata of local 

 vegetation, but, unlike the Sylviidae or old world warblers, they 

 show the highest degree of specialization both in regard to variety 

 of pigments and to white patterns. It seemed worth while, 

 therefore, to investigate the actual distribution of the species in 

 the three categories of high or open foliage, medium, and low 

 or close coverts. The results of such a study are embodied in 

 the following table in which the mean height of the bird's 

 occurrence has been compared with that of its average nesting 

 site as recorded by numerous observers, and its feeding beat 

 gauged with some accuracy. "While it has not always been 

 possible to distinguish clear lines of demarkation, on the whole 

 there is a surprising agreement among writers who allude to 

 the feeding levels of the warblers. 



WAEBLEKS WITH WHITE WING OE TAIL MARKING S. 



Or Highest Eangb. 



Vermivora bachmani 

 Compsothlypis americana 

 Compsothlypis a. usneae 

 Compsothlypis pitiayumi 



nigrilora 

 Peucedramus oUvaceus 

 Dendroica magnolia 

 Dendroica tigrina 

 Dendroica auduboni 

 Dendroica nigrescens 

 Dendroica virens 



Mniotilta varia 

 Protonotaria citrea 

 Vermivora chrysoptera 

 Vermivora pinus 

 Dendroica coronata 



Dendroica caerulesoens 

 Dendroica pensylvanica 



