292 TowNSEND, Bird Genealogy. [.July 



Eskimo, tind considers itself superior to the soutli-seeking Myrtle 

 Warbler, and it would probably pine for its northern home if 

 transplanted by force with the rest of the species to tropical regions. 

 In addition, its clannishness probably impels it to chose a summer 

 home apart from its southern relations. 



At present man cannot distinguish the northern from the 

 southern Myrtle Warbler, just as in the remote past, it is probable 

 that the Eskimo could not be distinguished from the Indian. In 

 time, however, aided by this inherent clannishness and love of 

 home, one might predict that a larger race of northern Myrtle 

 Warblers would be formed with thicker, stronger bills and more 

 muscular gizzards. Indeed I have endeavored to investigate these 

 three points in order to discover whether a beginning had been 

 made in the evolution of this new species, but I have not as yet 

 examined enough material to throw any light on the subject. 



One can easily see how important the element of clannishness is, 

 for without it interbreeding might for a long time, if not indefinitely 

 delay the birth of a new species. The importance of clannishness 

 in the evolution of races and species, has I believe never been given 

 due weight. 



As among men so among birds there are striking differences in 

 ambition and ability to succeed. Some men, some families, some 

 nations are progressive, — • they are always reaching out for new 

 opportunities and taking advantage of them. Others are retiring, 

 unambitious and contented to remain where they are. One of the 

 most remarkably progressive birds is the Horned Lark which has 

 spread to nearly every part of the continent, and has made each 

 part so much its home that it has adapted itself to the environment 

 to the extent of changing its own form and plumage. There are 

 now recognized fourteen different North American races or sub- 

 species of the Horned Lark. The pushing character of the bird 

 is shown in the recent extension of the breeding range of the 

 Prairie Horned Lark from the central part of the continent to New 

 England. In 1889 it was first recorded as breeding in Vermont, 

 and the same year in central Massachusetts. In 1903 it reached 

 the sea and bred at Ipswich and has come there to raise its young 

 ever since, meanwhile increasing in numbers throughout the New 

 England states.^ 



I Auk, XXI, 1904, p. 81. 



