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86 THE CONDOR [ Vo?,. V ant location-notes; for the greater becomes the danger of individua.ls becoming separated from the main flock. Bush-tits are usually hidden from each other in dense foliage. They have no directlye color-marks; therefore, being gregarious birds, the great value of their location-notes becomes apparent. Should a bush-tit lag so far behind as to be beyond hearing of his fellows, he may suddenly come to a realization of his loneliness; he at once becomes greatly perturbed, flitting to the tallest available perch, and uttering the last mentioned note reinforced into a regular cry for his companions. This is usually heard by the distant band and several similar answering cries inform the laggard of the di- rection the flock has taken. Off he goes in zigzag precipitation and joins his fel- lows with evident relief. We may judge from the strongly gregarious habit of the bush-tits that each individual gains from the community hfe. Such mites of birds surely have enemies, and a clue as to the identity of one enemy, at least, was brought to my attention last summer at Pacific Grove. There I took from the nest a young sharp-shinned hawk, the stomach of which contained an adult bush-tit, in pieces of course. Those of us who have closely observed the bush-tits to any extent will certainly recall the following experience at one time or another. I myself have witnessed it scores of times. A flock of bush-tits will be foraging as usual, with the ordinary uncertain medley of location-notes, when suddenly one or two birds utter several of the sharp alarm notes and then begin a shrill quavering piping. This is taken up by the whole flock, until there is a continuous monoto- nous chorus. At the same time every member of the scattered company strikes a stationary attitude in just the position it was when the alarm was first sounded, and this attitude is maintained until the danger is past. In nearly every case the danger is in the shape of a hawk, more especially of the smaller species such as the sharp-shinned or sparrow hawks. No matter how close the hawk approaches, the shrill chorus continues and even intensifies until the enemy has passed. The remarkable thing about this united cry, is that it is absolutely impossible to locate any single one of the birds by it. The chorus forms an indefinably confusing, all- pervading sound, which I know from personal experience to be most elusive. It may be compared in this respect to the sound of the cicada. This confusion-chor- us, as I think it might be appropriatety called, is a sure sign of the appearance of a small hawk even a long way off. Often long before I could myself locate the hawk, a neighboring band of bush-tits would have set up their cry, thus announc- ing its approach. It seems reasonable to infer' that this monotonous chorus of un- certain direction, at the same time as it sounds a general alarm, serves to conceal the individual birds, all of which at the same time maintain a statuesque, motionless attitude. Their colors also harmonize closely with the shadows'of the foliage. The whole evidently forms a composite protective device, which must be, as a rule, effectual. Scarcely any attention is ever paid by the bush-tits to large hawks, such as buteos, or to other large birds such as turkey vultures, pigeons, or jays. The bush-tits seem to be able to easily identify their real enemies at surprisingly long range. It is also of interest to note that mammals, large or small, are seldom stigma- tized by the confusion-chorus. If a person, or dog, or similar animal appears among a flock of bush-tits, a bird here and there may utter a'sharp repetition of the simple location-note very much augmented in volume. But after a moment's quiet, during which the birds intently survey the cause of the alarm, the flock goes on with its busy foraging, and usual miscellany of location-notes. Very often no attention at all is paid to a person, the birds flitting about heedlessly within a few feet of him.