exceptionally strong ones that they seem unable to get above them, and give to the stranger an appearance of being slow themselves. A good and experienced falcon or other rook-hawk will not be content with merely getting above her quarry before she makes her first stoop. She will go on ringing until she is so far above that the first stoop will be a good one. That is to say, that she may be able to get such an impetus upon her in the dash downwards as to rush up to the rook hand over hand, or, as the racing men say, as if he were standing still. And, having so run up to him, that she may, if she misses him, utilise the remainder of her impetus in shooting up again in preparation for a second stoop. The rook, on his part, when he finds the falcon above him, has to choose between two courses. Either he will persevere in trying to keep the air--and in that case must trust to quick turns and twists to elude the foe--or he will adopt the less valiant but almost equally dangerous alternative of a race to the nearest covert, with the necessity of eluding a certain number of stoops on the way. In the first case the flight will become a sort of improved version of coursing. Improved, because a bird has so much more varied chances of throwing out his pursuer than the hare, which can turn only either to the right or the left. He must always be on what the mathematicians call the same plane. The rook, on the other hand, may, if he likes, double simply to right or left. But he may also, if he prefers it, duck downwards or shoot upwards, allowing the hawk to pass over him or under him. Or he may turn partly upwards or downwards, and partly to either side. Thus there are an unlimited number of angles at which he can swerve away to avoid the stroke.