Rooks may be flown as soon as the passage hawks are trained. Old peregrines can of course be flown at any time (except when there are young rooks in the nests). But the winter and early part of the year is the best time, as later on the young crops preclude the possibility of riding over arable land; and it is impossible to ensure that the area of a flight shall be confined to the open downs. It is on some broad expanse of turf, however, that the quarry should be found, if you are to enjoy a good gallop and a proper view of the flight; for if you have to jump fences, you must needs take your eyes off the birds, and it may then be difficult to catch sight of them quickly again. You should not fly at a rook if there is any tolerable covert within half a mile down-wind, or a third of a mile on either side. The distance up-wind to the nearest covert need not be so great. When a rook is just rising off the ground, you can of course give him more law than when he is already on the wing. For, as has been said, height in the air counts very much more than distance along the flat. Even the small elevation from which a hawk starts as you carry her on horseback gives her a certain advantage over the rook which is only just off the ground. Rook flights often end more than a mile in a straight line from the start. But generally this is equivalent to saying that the distance flown has been more than double as much, by reason of the doublings and up-and-down dashes which both birds have made. In following a flight, it is best to keep about a quarter of a mile to leeward, or as near this as you can get, while keeping a good view of the scene. As the rook gets higher, still keep well to leeward, until you are pretty sure what covert the rook will ultimately make for. A little practice will generally enable you to make a pretty good guess, although perhaps for a while the rook may be heading a different way. If you are wrong, and find yourself thrown out, perhaps the best plan is not to ride hard in the vain hope of getting nearer, but take out your field-glasses, and watch the flight from about where you are. Each man out who knows enough about hawking to be able to take up a hawk, should carry a spare lure, so that, in case of a lost hawk, he may try for her in his own direction, while others are engaged on the same task in theirs. Agree beforehand, however, with the owner of the hawk, that if you find her you may take her up.