BLACK-AND-WHITE WARBLER 11 



Of the minor notes Andrew Allison (1907) says: "I know of no 

 other warbler except the Chat that can produce so great a variety of 

 sounds ; and since nearly all of the notes resemble those of other war- 

 blers, this is a most confusing bird to deal with during the busy season 

 of 'waves'." 



The call note often has a buzzing quality, and often runs into a long 

 chatter (also characteristic of the young bird), but it may be given 

 so sharply enunciated that it suggests the cliiy of the blackpoll. Al- 

 len (MS.) writes it cA^, "like pebbles struck together," and Cordelia 

 J. Stanwood (1910) renders it sptz^ saying "the sound resembled the 

 noise made by a drop of syrup sputtering on a hot stove." 



Field marks. — The blackpoll, in its spring plumage, and the black- 

 and-white warbler resemble each other in coloration, but the latter 

 bird may be readily distinguished by its white stripe down the center 

 of the crown and the white line over the eye. The contrast in the 

 behavior of the two birds separates them at a glance. 



Enemies. — ^Like other birds which build on the ground, the black- 

 and-white is subject, during the nesting season, to attacks by snakes 

 and predatory mammals. A. D. DuBois (MS.) cites a case in which 

 maggots destroyed a nestf ul of young birds. 



Harold S. Peters (1936) reports that a fly, Ornithoica con-fiuens 

 Say, and a louse, Myrsidea incerta (Kellogg), have been found in the 

 plumage of the black-and-white warbler. 



Herbert Friedmann (1929) says: "This aberrant warbler is a rather 

 uncommon victim of the Cowbird, only a couple dozen definite in- 

 stances having come to my notice. * * * xhe largest number of 

 Cowbirds' eggs found in a single nest of this Warbler is five, together 

 with three eggs of the owner." George W. Byers (1950) reports a 

 nest of this warbler, in Michigan, that held two eggs of the warbler 

 and eight of the cowbird, on which the warbler was incubating. His 

 photograph of the eggs suggests that they were probably laid by four 

 different cowbirds. 



Fall. — Several of the warblers show a tendency to stray from their 

 breeding grounds soon after their young are able to care for them- 

 selves, perhaps even before the postnuptial molt is completed and long 

 before the birds gather into the mixed autumn flocks. Among these 

 early wandering birds the black-and-white warbler is a very con- 

 spicuous species, perhaps because it is one of our commoner birds or, 

 more probably, because of its habit of feeding in plain sight on the 

 trunks and low branches of dead or dying trees and shrubs instead 

 of hiding, like other warblers, high up in the foliage. It may be that 

 the warblers we see at some distance from their breeding grounds thus 

 early in the season have already begun their migration toward the 

 south: they often appear to be migrating. 



