BLACK-POLLED WARBLER 403 



Kev. J. H. Langille (1884) states: "That song, though one of the 

 most slender and wiry in all our forests, is as distinguishable as the 

 hum of the Cicada or the shrilling of the Katydid. Tree-tree-tree- 

 tree-tree-tree-tree-tree^ rapidly uttered, the monotonous notes of equal 

 length, beginning very softly, gradually increasing to the middle of 

 the strain, and then as gradually diminishing, thus forming a fine 

 musical swell. * * * There is a peculiar soft and tinkling sweet- 

 ness in this melody, suggestive of the quiet mysteries of the forest, 

 and sedative as an anodyne to the nerves." 



On their nesting grounds in the W^iite Mountains of New Hamp- 

 shire and at Kent Island, Bay of Fundy, New Brunswick, I have 

 heard the full song of the blackpoll throughout the nesting season 

 but rarely after the young left the nest. I have seen them perched 

 in full view at the very top of a spruce or fir tree pouring forth their 

 simple but earnest song. They have a call note, a high-pitched lisp 

 which resembles zeet^ and when suddenly surprised or alarmed they 

 utter a strong chirp. 



The blackpoll is usually silent in autumn, but at times it has been 

 heard in full song late in the season, after having acquired its winter 

 plumage. During the fall migration the diurnal note tsit is the com- 

 monest heard. 



Though the blackpoll does not excel as a songster, its song has one 

 characteristic which makes it stand out in marked contrast to all 

 others. Albert Brand (1938), who determined the vibration frequen- 

 cies of 59 passerine birds, found that the song of the blackpoll has the 

 highest pitch of all the bird songs he studied. Its average frequency 

 was 8,900, midway between C sharp 8 and D 8, or over an octave 

 above the highest tone on the piano. The blackpoll also produced 

 the highest avian frequency studied, 10,225, a quarter tone under 

 E 8. The lowest frequency recorded in various songs of the blackpoll 

 was 8,050. By comparison, the mean frequency in songs of the north- 

 em pine warbler is 4,150, the highest 5,125, and the lowest only 3,300. 

 Indeed the song of the blackpoll is of such a high frequency that it 

 is well beyond the range of hearing of many persons. I must admit, 

 in recent years, I have observed the blackpoll singing and could see 

 by its posture and the movements of its beak and throat that it was 

 singing, but I was unable to hear the song. 



Enemies. — The blackpoll is subject to the usual enemies of other 

 woodland birds, but all these apparently exact an insignificant toll 

 when compared to the hazards experienced during migration. In 

 crossing the wide expanses of the Caribbean Sea from the winter 

 quarters in South America, some of them take refuge on passing boats 

 during bad weather, but the vast majority after battling adverse 

 winds and storms reach the Florida and Gulf coast in a weakened or 



