1S84J. BiCKNKLl, o>i the Si)igiitg of B/r(fs. 213 



Dendroeca caerulescens. Black-thkoatkd IJlue 



WyVKHLKR. 



Passes by in full song in May. Tliout^h usvially silent on its 

 migration in the autumn, it is sometimes to be numbered among 

 the birds which sing at that season. On September 23, 187S, a 

 morning when birds were abundant and active, and a number 

 voiceful, including the House Wren, Blue-headed and White- 

 eyed Vireos, Swamp and Song Sparrows, several of these 

 Warblers were observed in fine plumage and full song. It 

 an"ives in autumn with renewed plumage and usually with little 

 fat. 



Dendrceca coj-onata^ Yellow-rumped Warbler; D. maculosa^ 

 Black-and-yellow Warbler ; D. pennsylvanica^ Chestnut-sided 

 Warbler ; D. castanea^ Bay-breasted Warbler ; D. striata^ 

 Black-poll Warbler ; D. blackburnice^ Blackburnian Warbler ; 

 D. virens^ Black-throated Green Warbler ; D. fahnai'um hypo- 

 chrysea^ Yellow Red-poll Warbler ; D. tigrina^ Cape May 

 Warbler. 



All of these spring and autumn migrants sing as the}- pass 

 north, but are silent when they return. 



Siurus auricapillus. Oven-bird. 



Toward the end of June the song of this bird, which has been 

 so constantly accentuated through our woodland for two months, 

 becomes less frequent, and though heard into July, comparativel}' 

 few individuals sing through the month. In some seasons I have 

 missed it after the first week, but in others have heard it with 

 some regularity through the second week, with rarely a chance 

 song in the week following ; Juh' 23 is my latest date. 



The second song-period occurs in August, and is transient and 

 irregular ; with varying seasons shifting a little to either side of 

 the middle of the month. Rarely it continues imperfectlv into 

 September. August 9 and September 5 constitute extreme 

 boundary dates, but at neither limit w^ere.the songs perfect. As 

 if the power of song was gradually regained at the maturity of 

 the new plumage, the time of silence which follows the breeding 

 season, accompanying the moult, is finally interrupted, not with 



