As for the short-winged hawks, and for such others as will not keep on the wing willingly without going to perch, they must be exercised chiefly by the device known as calling off. The most effective plan is that mentioned in Chapter VI., where two men go out, and, standing at a distance from one another, alternately bring the hawk across the intervening space by showing the lure or the outstretched fist. If two men are not available the hawk may be deposited on a railing, gate, or post, and the falconer may walk away, hiding his hands, and when he is as far off as he likes, or as the hawk will allow him to go, may call her and reward her with a few morsels, and then put her down again for the operation to be repeated. A trained hawk will often follow the falconer about for a long time, as he walks along, waiting a while in expectation of being called, and, if disappointed, flitting to a nearer resting-place, or coming right up to him on the chance that his hand will be held out; and if it is not, betaking herself to a neighbouring tree or other convenient place. Such excursions as these, in a park or on the downs, with a favourite hawk always in sight, either in the air or on a conspicuous perch of her own choosing, afford an opportunity of indulging her with the best possible sort of weathering. It is the nearest approach which can safely be made to giving trained hawks their liberty. It is a common thing with writers on hawking to recommend their readers, when a trained hawk is out of sorts, to put her on a pair of hack-bells, and turn her out to hack for a while. I desire to speak with all respect of a practice which has doubtless been often attempted with success; but I am compelled to say that my own experience is altogether unfavourable to any such experiment. Attempts that I have known made to keep trained hawks at hack have not only failed, but have over and over again entailed the loss of the bird operated upon, sometimes for a time, and sometimes permanently. A strong and clever hawk, even if she is a bit unwell, and even if she is weighted heavily, will manage to kill something, if she has a real mind to it; and even if she does not, her wanderings may lead her first out of sight, and then into some neighbouring field or place, where a stray gunner may make an end of her. I am not able to advise beginners to turn their hawks loose for any longer time than they themselves or some agent can be near at hand, unless it be in the case of a kestrel or hobby, or other hawk which has never killed wild birds regularly in fair flight.