137 



that are found in summer, and breed, should be distinguished 

 from those that breed further nortii and come to us only in 

 winter, or in spring and fall during their migrations. 



For these reasons I have added remarks after each species 

 indicating its season and relative abundance as far as known 

 to me, and also, when possible, the time of laying the eggs or 

 of hatching the young. I regret that I have not been able 

 to make these observations more complete, and would call 

 the attention of our naturalists residing in the country to 

 these important questions as offering a field for useful and 

 interesting study. The time occupied in incubation also, is 

 known for very few of our most common birds. Another 

 interesting question, upon which I trust the present list will 

 throw some light, is the determination of the boundaries 

 between the Canadian Fauna and that of the Eastern Uni- 

 ted States, or Alleghanian Fauna.* Although many of our 

 common birds range during the breeding season from Vir- 

 ginia, or even farther south, to Labrador, yet when we com- 

 pare the birds of Canada or northern Maine, as a whole, 

 with those of Massachusetts or any more southern locality, 

 we find them very different. Many of the most common 

 Canadian summer birds visit us only in winter, or are seen 

 only during there passage to and from a still more southern 

 climate, and other species that reside there during the whole 

 year are never seen, except in rare instances, farther south 

 than Northern New England. 



Among the first, I will mention for examples the common 

 Blue Snow Bird, Pine Finch, Canada Jay, White-winged 

 Crossbill, Pine Grosbeak, Black-poll Warbler, Fox-colored 

 Sparrow and many kinds of Ducks and Waders. Among 

 the resident birds of Canada, die Spruce Partridge, Ptarmi- 

 gan, Hawk Owl, and Black Three-toed Woodpecker are 

 examples. On the contrary, many of our common species 

 do not breed in Canada or are rare there except in some 

 peculiar localities, while other species that are abundant 

 here become less common northward and are gradually re- 

 placed by allied species having similar habits, though not 

 always belonging to the same genera. 



* The term " Alleghanian Fauna" was applied in 1853 to the fauna of the middle 

 and Eastern States, by f rof. L. Agassiz, in " A Sketch of the Natural Provinces 

 ■of the Animal World and their Relation to the difierent Types of Man," in Nott and 

 Gliddon's " Types of Aianlcind." 



ESSEX INST. PROCEED. VOL. iii. 18. 



