GENERAL TRAITS OF WARBLERS 239 



Central and even South America. Some of the Warblers that 

 push farthest north in spring are also those that penetrate farth- 

 est into South America, it being not at all a question of balan- 

 cing a far-north spring migration with a less extended return 

 movement in the fall. The passage of the Warblers keeps the 

 collectors busy, and thousands, doubtless, of these delicate and 

 attractive birds meet their fate each year in this way. The 

 great variability in color, according to age, sex, or season, which 

 nearly all the species display, no less than their real beauty, 

 encourages the acquisition of large suites of specimens, and 

 stimulates the collector to rival his fellows in the possession of 

 the most highly plumaged spring males, or in the discovery of 

 some of those indifferently feathered females and young which 

 sometimes puzzle the most expert ornithologists ; and almost 

 every local collection may boast its Warbler prize. In the 

 breeding season, especially in New England and other northerly 

 portions of the United States, the riper and more thoughtful 

 naturalist, less avaricious of mere possession, finds ample scope 

 for the exercise of his craft in his leisurely studies of the 

 habits of Warblers and his diligent search for their nests. Nor 

 was it long since that the nest and eggs of many of the com- 

 monest species were rarities or even novelties, so slowly did we 

 acquire our knowledge of this kind; and even now so much 

 remains to be ascertained, that the field may be considered open 

 to the diligence and ability of whoso may will to enter it. 



Only a single species of Dendrceca — the familiar and ubiqui- 

 tous Summer Warbler — ranges regularly across the continent, 

 though each side occasionally receives a straggler from the 

 other, like D. coronata and D. townsendi. The abundance of 

 the genus in the East contrasts sharply with its poverty in the 

 West. Audubon's Warbler is the most numerously and widely 

 diffused species, corresponding to the Yellow-rump of the East. 

 D. nigrescenSj which may perhaps be considered to represent 

 1). coerulescens, is another common species. The Eastern D. virens 

 is the type and only representative of a little subgroup, which, 

 in the West, furnishes no fewer than three species; though chry- 

 soparia can hardly be called Western, as it only reaches Texas, 

 D. occidentalis and D. toicnsendi being the representatives of 

 the virens group in other parts of the West. Finally, the East- 

 ern D. dominica is replaced in the Southwest by the lately dis- 

 covered Grace's Warbler. 



In drawing comparisons between the Eastern and Western 



