woodpecker shows a greater tendency to deviate in this direction; but I have had no opportunity of doing this.
With regard to the other assertion—namely, that the tree-creeper never descends the trunk of the tree—this is at least not true without qualification, for I have seen it do so backwards, with a curious and, as it seemed to me, a quite special motion. It was quick and sudden, carrying the bird an inch or so down the trunk, when it ceased and was not repeated: a jerk, in fact, but of a much more pronounced character, made thus backwards, than any of the little forward jerks, in a toned—one might almost sometimes say a gliding—succession, of which the ordinary "creeping" consists. The first time I saw this action (to dwell upon) it constituted a perpendicular descent, but my eye was not full on the bird at the moment, so that I only observed it imperfectly. On the second occasion I saw it quite plainly, and this time the bird jerked itself sideways as well as downwards, stopping in the same abrupt manner, though whether it made two short quick jerks or only one, I could not be quite sure of I think it was two, but that only the last one gave the jerky effect. It would thus seem that the tree-creeper might really progress in this way, for some little while, if it wished to. The tail must almost of necessity be raised, or the stiff, pointed feathers would catch in the roughnesses of the bark; but, either from the quickness of the action, or the slight extent to which it was lifted, I did not notice this.
I have also seen the great green woodpecker make exactly this same motion, downwards and backwards, on the trunk to which he was clinging, so
