Excerpt from Fragments of the Natural History of Pennsylvania, Vol. 1 It is, I think, in general, a just observation, that our Spring and Summer birds of passage continue with us about six months, and are absent for the same length of time. Accordingly, those birds which arrive early in the spring disappear early in the autumn, and those which arrive late in the spring do not disappear until late in the au tumu. Our late springs are commonly succeeded by late and warm autumns, which, by keeping alive the numerous species of insects, which are the favourite food of almost all our summer birds of passage, detain these birds for a considerable time among us. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.