There are cases, however, in which the relationship between the birds is very puzzling. In the following scene, from my notes, there is a hint of hostility or remonstrance, but a suggestion of courtship also--out of place, it seems, in autumn between two female birds. “October 15, 1935. Two birds are in a large, bare maple tree; one is noticeably larger than the other, but neither one has a red occipital patch. They keep near each other, one following the other by short, quick flights. They perch perfectly motionless for a moment a foot or two apart; then both together sway their heads, swinging them quickly down and up to one side, down and up to the other side. The swing is very rapid, like the wink of an eye. They flit their wings upward and outward, also with the speed of a wink, over and over--all this without a sound. They fly behind a branch sometimes but keep mostly in sight of each other, and, although neither attacks, each seems wary of attack and dodges away when approached. They sometimes alight on very slender branches, and once a bird goes to the ground where it stands with its head held high up. They move very actively and lightly, with never the slightest blundering, flitting silently and easily from branch to branch.” The following astonishing story, taken from William Brewster’s Concord journal (1937), tells of a case in which antagonism of unknown cause leads to the killing with brutal violence of a female downy by a male: March 20, 1911. We were in the dining-room, consulting about the day’s work, when we heard the _tchick_ note of the Downy Woodpecker repeated almost incessantly and very rapidly just outside. For a moment or more we paid no attention to it. But something unusual in its quality and its insistence soon led me to look out and this was what I saw: