NORTHERN AND MARYLAND YELLOWTHROATS 543 



the breeding and winter ranges overlap and the literature pertaining 

 to these two forms is so intermixed that they are not easily separated. 



The species of Geothlypis respond more readily to the influences of 

 the environment than do other American warblers. As a result 12 

 subspecies of trichas have been recognized by the 1931 A. O. U. Check- 

 List and subsequent supplements. Of these, 4, trichas, 'brachidactyla, 

 ignota, and typhicola are in eastern United States and the other 8, 

 OGcidentalis, campicola, sinuosa, chryseola, scirpicola, arizela, in- 

 sperata, and wiodesta are represented in the western part of the 

 country. 



The color pattern of the 12 subspecies is similar; and they vary 

 chiefly in minor differences of size and intensity of color. In a num- 

 ber of instances, the great individual variation which characterizes 

 these birds so obscures their subspecific differences that determination 

 of skins is often difficult and p'ositive identification in the field, espe- 

 cially where the ranges overlap, is impossible. 



Of the two forms included in this life history, the northern yellow- 

 throat differs from the Maryland yellowthroat, in the male, in its 

 larger size, and by reason of its more greenish upper surface, more 

 whitish frontal band of grays, more extensively yellow posterior parts, 

 and its usually brownish flanks. The female of the northern is simi- 

 lar to the Maryland but is larger, more greenish above, and slightly 

 paler. 



The breeding range of the northern yellowthroat extends from 

 Newfoundland, Labrador and Quebec south to New Jersey, northern 

 Pennsylvania and West Virginia, while that of the Maryland extends 

 from southern Pennsylvania south to eastern Texas and northern parts 

 of Georgia and Alabama. 



Throughout most of its breeding range the yellowthroat ranks as one 

 of the abundant warblers. Because of the striking and easily recog- 

 nized plumage of the male, especially the bright yellow throat and 

 contrasting black mask, and its characteristic syllabic and easily 

 memorized song it is one of our best-known birds. The modestly 

 colored female is more difficult to identify, as it may be confused, by 

 the beginner, with other similarly colored warblers. The yellowthroat 

 seldom visits the habitation of man ; it prefers wild lands, especially 

 those grown up with briers and low brush. Its favorite nesting haunts 

 are in the tangled vegetation of brook-sides or margins of swamp 

 woodlands or among the grass and sedges of the marshes, where it 

 frequently shares the company of such birds as the swamp sparrow 

 and the marsh wrens. 



When invading its haunts one is impressed with the vigorous per- 

 sonality of the male. He nervously raises his alarm with a variety 

 of scolding, interrogative chirps and chattering notes and his dark 

 inquisitive eyes sparkle with excitement through the black masks. 



