Again, Leroy says of the fox:—“He smells the iron of the trap, and this sensation has become so terrible to him, that it prevails over every other. If he perceives that the snares become more numerous, he departs to seek a safe neighbourhood. But sometimes, grown bold by a nearer and oft-repeated examination, and guided by his unerring scent, he manages, without hurt to himself, to draw the bait adroitly out of the trap.... If all the outlets of his den are guarded by traps, the animal scents them, recognizes them, and will suffer the most acute hunger rather than attempt to pass them. I have known foxes keep their dens a whole fortnight, and only then make up their minds to come out because hunger left them no choice but as to the mode of death.... There is nothing he will not attempt in order to save himself. He will dig till he has worn away his claws to effect his exit by a fresh opening, and thus not unfrequently escapes the snares of the sportsman. If a rabbit imprisoned with him gets caught in one of the snares, or if by any other means one should go off, he infers that the machine has done its duty, and walks boldly and securely over it.”[46] Lastly, this author gives the case, which has since been largely quoted—although its source is seldom given—of crows which it is desired to shoot upon their nests, in order to destroy birds and eggs at the same time. The crows will not return to their nests during daylight, if they see any one waiting to shoot them. If, to lull suspicion, a hut is made below the rookery and a man conceal himself in it with a gun, he waits in vain if the bird has ever before been shot at in a similar manner. “She knows that fire will issue from the cave into which she saw a man enter.” Leroy then goes on to say:—“To deceive this suspicious bird, the plan was hit upon of sending two men into the watch-house, one of whom passed on while the other remained; but the crow counted and kept her distance. The next day three went, and again she perceived that only two returned. In fine it was found necessary to send five or six men to the watch-house in order to put her out of her calculation.”