Some observations on the migration of birds. By the late Edward Jenner, M. D. F. R. S.; with an Introductory letter to Sir Humphry Davy, Bart. P. R. S. By the Rev. G. C. Jenner

Abstract The author’s intention in this paper is not to give a general history of the migration of birds, but to adduce some hitherto unnoticed facts respecting the causes which excite the bird at certain seasons of the year to quit one country for another. Among these the most prominent are certain changes in the generative organs, and the necessity of a climate or country where they can be better accommodated with succours for their infant brood than in that from which they depart. He also adduces facts to prove that their departure from this country is not in consequence of change of temperature or scarcity of food, but the result of the accomplishment of their errand, namely, the incubation and rearing their young. The author then offers some remarks on the winter birds of passage, tending to show that they quit this country in spring in quest of a situation better adapted to their intended purpose, and that they are actuated by the same impulse in leaving this country that causes the spring birds to come to it, and not by want of food. That the emigration of the winter birds is less complete than that of the spring migrators, and that some species, especially the wild duck and wood-pigeon, breed here.