On the day of this first adventure began a mysterious performance, the meaning of which I did not understand till later, when it became very familiar. It opened with a peculiar call, and its object was to rouse the young to follow. So remarkable was the effect upon them that I have no doubt a mob of kingbirds could be brought together by its means. It began, as I said, with a call, a low, prolonged cry, sounding, as nearly as letters can express it, like "Kr-r-r-r! Kr-r-r-r!" At the same moment, both parents flew in circles around the tree, a little above the nest, now and then almost touching it, and all the time uttering the strange cry. At the first sound, the three young kings mounted the edge, wildly excited, dressing their plumage in the most frantic manner, as if their lives depended on being off in an instant. It lasted but a few moments: the parents flew away; the youngsters calmed down. In a short time all the nestlings were accustomed to going out upon the branch, where they clustered together in a little row, and called and plumed alternately; but one after another slipped back into the dear old home, which they apparently found it very hard to leave. Often, upon coming out of the house, after the imperative demands of luncheon or dinner had dragged me for a time away from my absorbing study, not a kingbird, old or young, could be seen. The oak was deserted, the nest perfectly silent. "They have flown!" I thought. But no: in a few minutes small heads began show above the battlements; and in ten seconds after the three little kings were all in sight, chirping and arranging their dress with fresh vigor, after their nap.