June, 1902,] Summer Birds of Lake Erie's Islands. 283 



sitiou. Also a few plum trees. The club and dwelling house 

 have driven the gulls and terns away. 



The row to North Harbor in the gloaming discovered to us 

 converging lines of Purple Martins. A near approach to the 

 island revealed the point of convergence to be the largest tree on 

 the island, at its southernmost point. It was not possible to even 

 estimate approximately the numbers forming this roost, but the 

 tree was clearly well filled. There must have been 2000 birds 

 among its branches. We thought we had heard and seen terns be- 

 fore. Camp had to be pitched right in the midst of them. Here 

 we had the first sight of terns roosting perched upon the trees. 

 They were a little awkward in getting settled, but seemed per- 

 fectly at home once the wings were safely folded. 



The dense growth of trees and brush, over the largest part of 

 the island, made a count of the nests impossible. It is safe to say, 

 however, that the population exceeded all that we had thus far 

 seen. Here, too, we found nests and dry eggs of Red-winged 

 Blackbirds and Bronzed Grackles. Here, on this most northern 

 outlier of the group, were Wood Pewee, Kingbird, Cedar Wax- 

 wing, Goldfinch, and even Carolina Wren, and a probable Red- 

 e^-ed Vireo. On the sunny eastern side we saw the most very 

 young terns, and several well fed black snakes. The birds and 

 snakes seemed to be the only land vertebrates. 



The island itself is interesting, and but for the terns would be 

 a delightful place to spend the summer months were it not so far 

 frnm any base of supplies. Where the rocks are exposed they 

 are deeply furrowed by glacial scratches. 



A few hours spent on East Sister island was fruitful in the dis- 

 covery of species not seen hitherto. Here, again, were the Caro- 

 lina Wrens and the others seen on North Harbor, and besides 

 them the Cardinal, the Marsh Hawk, Crow, Indigo Bunting, Song 

 Sparrow, Yellow-billed Cuckoo, Redstart and Robin. East Sister 

 is an island so large in extent and so varied in physical features 

 and vegetation that one is not surprised to find a large and varied 

 bird population. Of course these six islands : the Hen and three 

 Chickens, North Harbor and East Sister, do not belong to Ohio, 

 being in the Canadian possessions, but they lie so directly in con- 

 tinuation with the Bass group that a study of their population is 

 necessary to understand fully the more southern islands. 



This brief study of this really large group of islands proved 

 what I had every reason to expect, that it is by this route that 

 many of our migratory species reach Canada. It forms a natural 

 highway for the birds of weaker wing who wander westward along 

 the shore of the lake to find here an easy crossing place. And it 

 is this stream of migration whose strong current sweeps along 

 with it such usually southern species as the Cardinal and Carolina 

 Wren until they find congenial quarters upon the islands well to 



