It catches its prey and ordinarily acts like a rather dull flycatcher, perching on some dead tree, swooping on insects and then returning to its perch, and never going on the ground to feed or run about.

In examples so conspicuous the movement is obvious enough; but in the case of rarer species, for instance, the olive-sided flycatcher, who can tell whether, when first observed, it was new to naturalists merely, or to this part of the country, or to the earth generally?