Passanger Pigeon
Blue-mountain Warbler
Hemlock Warbler
But the most remarkable characteristic of these birds is their associating together, both in their migrations, and also during the period of incubation, in such prodigious numbers as almost to surpass belief, and which has no parallel among any other of the feathered tribes on the face of the earth with which naturalists are acquainted.
These migrations appear to be undertaken rather in quest of food, than merely to avoid the cold of the climate, since we find them lingering in the northern regions, around Hudson's Bay, so late as December; and since their appearance is so casual and irregular, sometimes not visiting certain districts for several years in any considerable numbers, while at other times they are innumerable.
