TREE SPARROW 1159 



Dui-ing June the males sing continuously, one song follo^^ing another 

 in rapid succession. On one occasion I counted four in a minute, fol- 

 lowed by a brief interval while the bird flew to another perch. There is 

 no siesta period in this cool climate. Night singing, in spite of the 

 half dark twihght of the midnight sun, is infrequent. On several 

 occasions when I watched nests all night, singing decreased con- 

 spicuously after 9:15 and the last song was heard at 10:15 p.m., al- 

 though other species were still active. Although there was full 

 dayhght at 2:15 a.m. the first tree sparrow song was not recorded until 

 2:45. 



In mid-July singing becomes less frequent as males take over their 

 share of feeding the young. During August the song can be heard 

 occasionally on warm still days. 



During fall migration the song is heard not infrequently during 

 November, a thin, \nry note that rarely reaches the fullness of the 

 true breeding song. February is the beginning of the spring tune-up, 

 and by mid-March the hedgerows ring ^nth the true summer song. 

 With the passing of most of the males, singing becomes less frequent 

 after the middle of April. 



That melodious, warbhng twitter of a winter flock which Thoreau 

 (1910) so aptly describes as the "tinkle of icicles" cannot, according 

 to Saunders (1929b) be considered true song, as it is not a courtship 

 performance but merely the contented utterance of a well-fed flock. 

 It can be heard at any time and in any weather throughout the wdnter 

 a cheerful, tri-syllablic warble, teedle eet, teedle eet. 



Call notes include the soft tsip on winter feeding grounds, a some- 

 what sharper alarm note heard both winter and summer, an imperious 

 little breeding call of the male chek-chek-ckek, chek, chek, the female's 

 response, a soft whey-whey-whey-whey-wkey, and w hispered ts-ts-ts-ts-ts. 

 Sometimes when the male came to feed the young, the brooding female 

 uttered rapidly and with rising inflection, a series of consonants which 

 I recorded in by field notebook as "pppppppt," or a low ticking note. 

 Sometimes both parents came to the nest simultaneously and stood 

 fondly over their family, uttering low cooing notes and touching bills 

 tenderly. 



Development of voice in the young was traced from the first soft 

 tseeeeeeee at 5 days (Baumgartner, 1938a) to the noisy food call at 

 9j'2 days as the young left the nest, when both adult and nestling 

 uttered a raucous aah aah aah aah. 



Enemies. — Man, the archenemy of many birds, affects the tree 

 sparrows very little. Too small for game, beneficial in habits, incon- 

 spicuous in manner, they are seldom noticed in winter, and in summer 

 retreat mainly beyond the reaches of civilization. Predatory ani- 

 mals, such as the bird hawks, owls, shrikes, weasels, and the domestic 



