THE WARBLERS 



(Family Mniotiltidae) 



BY A. A. ALLEN, PH.D. 



ASSISTANT PROFESSOR OF ORNITHOLOGY, CORNELL UNIVERSITY 



PERHAPS no family of birds plays a greater part in 

 the protection of our forests than the warblers. 

 Being primarily woodland birds, they arrive in the 

 spring when the leaves are just beginning to unfold and 

 the hordes of caterpillars emerging from the eggs in which 

 they have passed the winter. Not a twig goes unnoticed, 

 scarcely a bud unscrutinized, as this army of busy trav- 

 elers sweeps on to its northern breeding ground. During 

 April, May, and June, when the migration is in progress, 

 they practically rid the trees of insect pests which other- 

 wise would defoliate them in a single season. 



But besides this economic appeal they have an aesthetic 

 one, and certain it is that no group of birds is more attrac- 

 tive to the beginner in the study of ornithology than these 

 multi-colored, active, forest-dwellers. At first they baffle 

 him with their great variety of colors and rather nondescript 

 songs, but they lure him ever to more persistent effort by 

 challenging his acuteness, his perseverance, his woodcraft. 



A WATER SPRITE 



A Louisiana water-thrush with larva; of the black fly for its young. Rocky 



streams and dashing cascades make a home for this graceful warbler. 



The Mniotiltidae is one of the larger families of birds, 

 containing about one-hundred and fifty-five species con- 

 fined entirely to the new world. In summer they are 

 found from northern Alaska to Argentina but -only about 

 fifty-five species visit the United States. Forty species arc 

 confined to South America, thirty to Central America and 

 Mexico, twenty to the West Indies, and ten to the Gala- 

 pagos Islands. Thus it will be seen that, although the 

 warblers are undoubtedly of tropical origin, they now 

 reach their highest development in North America. Of 



the North American species, it seems that quite a number 

 have come into the United States from the West Indies, 

 while others have originated in Mexico. The former, 

 which include principally the genus Dendroica, notably 

 the black-throated blue, the black-throated green, the 

 magnolia, the chestnut-sided, and the bay-breasted war- 

 blers, are, as yet, confined mostly to eastern United States. 



THE DOMED NEST OP THE OVEN BIRD 



The oven birds and water-thrushes belong to the warbler family in spite of 

 their common names. They are terrestrial birds, the oven bird spending its 

 life among the leaves of the forest floor. Its ordinary song resembles the words 

 "teacher teacher teacher teacher," but it has also a remarkable flight song. 



Those of Mexican origin have spread over both the east 

 and the west so that, today, there are about twice as 

 many species in eastern United States as in the west. 



Each species is characteristic of some particular faunal 

 area as well as some particular habitat. Thus, after they 

 have settled down for the summer, wc find that certain 

 species never nest north of Virginia, others never south of 

 New York or Pennsylvania, and still others always north 

 of the boundary of the United States. Among the war- 

 blers that go far north to breed might be mentioned the 

 blackpoll, the Tennessee, the palm, the myrtle, the bay- 

 breasted, the blackburnian, the orange-crowned, and the 

 Cape May warblers, and a little farther south, the mag- 

 nolia, the black-throated blue, the black-throated green, 

 the Nashville, the mourning, the Canadian warblers, and 

 the water-thrush. The common breeding warblers of the 

 northern United States are the yellow warbler, the red- 

 start, the oven-bird, the yellow-throat, the black and 



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