The Numbers and Local Distribution in Summer of Illinois Land Birds of the Open Country

Abstract

It was hence particularly desirable that additional data should be collected during at least a part of a second year in order that it could be seen to what extent those of the first year might have a somewhat general application, and in order also that by a combination of the two sets of data a broader basis might be had for generalizations of more stable value; and this was done by a substantial repetition, during the three summer montsh of 1909, of the summer program of 1907.