Vol. XXVI 

 1909 



I Trotter, Land-Bird Fauna of X. E. America. 227 



White- throated Sparrow, the Flycatchers and others mentioned 

 above, seem to me to form a group that established themselves as 

 breeders in the boreal zone at an early day after the uncovering of 

 the land by the retreating glaciers, spreading into the Nova Scotia 

 peninsula most likely soon after or possibly during the reelevation 

 of the land bridge. In reality they do not belong to the ancient 

 boreal fauna as just outlined, but represent an early advance 

 movement of the more southern bird life, a movement that is still 

 in progress. These birds are all typical long distance migrants 

 rather than wanderers and, unlike the true boreal wanderers, they 

 leave a wide hiatus of unoccupied territory between their breeding 

 grounds and their winter quarters. This is especially true of 

 the Thrushes, Wood Warblers, the Vireo, and Flycatchers which 

 feed on fruits, winged insects, and soft larva, while the seed-eating 

 species like the Junco, the White-throated and other Sparrows, 

 are not compelled to move so far and hence occupy a winter zone of 

 territory much nearer to their breeding haunts. Yet even such 

 northerly breeders as the Fox Sparrow and the White- crowned 

 Sparrow leave a considerable breadth of unoccupied territory 

 between their summer and winter ranges. 



Sometime during the post-glacial period many purely transition 

 or Alleghanian species spread into the Nova Scotia region, probably 

 by way of the land connection, but the significant fact is that this 

 movement is still going on and that some species, like the Chipping 

 Sparrow and possibly the Goldfinch, have not yet invaded the 

 entire territory. That they have come by the Amherst neck of 

 land from the main continent is also evident since these birds do 

 not appear to have reached as yet the more southern districts of 

 the peninsula, at least along the eastern side, so far as my observa- 

 tions go. Still more significant is the support given to this view by 

 Downs in his 'Catalogue of the Birds of Nova Scotia ' ' in remarking 

 upon certain species. From what I gather his observations are 

 chiefly in the neighborhood of Halifax and in the more western parts 

 of the Province. Of the Chipping Sparrow he says: "Lately 

 became rather common"; of the Field Sparrow, "not very com- 



1 'A Catalogue of the Birds of Nova Scotia,' by A. Downs. Proceedings and 

 Transactions of the Nova Scotia Institute of Natural Science, Vol. VII, pp. 142-178, 



188S. 



