first bird is passed by two others, then passes one of these again, and remains the second as long as I can see them.
"Another long flight that seems leaderless. With the 'caw' comes a note like 'chug-a, chug-a, chug-a' (but the u more as in Spanish), and others that I cannot transcribe. This flight goes on almost continuously—I mean without a distinct gap dividing it from another band—for about ten minutes, when another great multitude appears, flying at an immense height and all abreast, as it were—that is to say, a hundred or so in a long line of only a few birds deep. This, perhaps, would be the formation best adapted for observing and following one bird that flew well in front, but I can see no such one. All these birds are sailing calmly and serenely along, giving only now and again an occasional stroke or two with the wings. Now comes a further great assembly, in loose order, all flying in the same direction. A characteristic of these large flights of rooks is that their van will often pause in the air and then wheel back, circling out to either side. The rearguard is thus checked in its advance, the birds of either section streaming through each other, till the whole body, after circling and hanging in the air for a little, like a black eddying snowstorm (all at a great height), wend on again in the same direction, towards their distant roosting-place. With the air full of the voice of the birds, there is no caw—only the flexible, croodling, chirruppy note that has a good deal of music in it, as well as of expression. This note, I think, is what I have put down as 'chug-a, chug-a, chug-a.'
