BIRDS OF ESSEX COUNTY. 295 



280 [667] Dendroica virens (Gmel.). 

 Black-throated Green Warbler. 



Very common summer resident ; May 1 to October 1 5 ; average date of 

 arrival for eight years, May 4. 



Eggs: May 30 to June 17. 



All the Warblers vary considerably in their songs, many having two songs 

 quite unlike. In the case of this Warbler, the variations are less marked, but 

 on one occasion I heard an interesting song which I at last traced to a Black- 

 throated Green Warbler. The bird was sitting in a small evergreen and unless 

 I had actually seen him sing, I should never have supposed it was produced by 

 this species, as it was totally unlike the usual song. The first two notes were 

 whistled quite clearly, and the bird seemed to say wkoit ivlioit sweet sweetsby. 

 The common song, zee zee, se, ze, ze, always brings with it the breath of white 

 pines, and one generally takes the song on faith that the bird is there, for it is 

 difficult to see the singer in their dark tops. 



28 r [671] Dendroica vigorsii (Aud.). 

 Pine Warbler. 



Common summer resident ; April 1 1 to October 3 1 . 



Eggs : May 15 to June 16. 



There are many groves of pitch pines in Essex County, some of these, as 

 at Magnolia, close to the sea, and here it is that the Pine Warbler makes its 

 home. 



282 [672] Dendroica palmarum (Gmel.). 

 Palm Warbler ; Red-poll Warbler. 



Rare autumn transient visitor ; September 26 to October 4. 



Mr. Ralph Hoffmann saw a bird of this species at Ipswich on September 

 26th, 1903. The next day I saw one, perhaps the same bird. Again, on Octo- 



