"K-k-k-k, kow-kow-ow-kow-ow!" is a familiar sound in many localities, but the large. slim,, pigeon-shaped, brownish-olive bird that makes it, securely hidden in the low trees and shrubs that are its haunts, is not often personally known. Catching a glimpse only of the grayish-white under parts from where we stand looking up into the tree at it, it is quite impossible to tell the bird from the yellow-billed species. When, as it flies about, we are able to note the red circles about its eyes, its black bill, and the absence of black tail feathers, with their white "thumb-nail" spots, and see no bright cinnamon feathers on the wings (the yellow-billed specie's distinguishing marks), we can at last claim acquaintance with the black-billed cuckoo. Our two common cuckoos are so nearly alike that they are constantly confused in the popular mind and very often in the writings of ornithologists. At first glance the birds look alike. Their haunts are almost identical; their habits are the same; and, as they usually keep well out of sight, it is not surprising if confusion arise.