The Peregrine: 50th Anniversary Edition: Afterword by Robert Macfarlane. Robert MacFarlane

inhibited by a code of behaviour. It seldom chases prey on the ground or pursues it into cover, in the manner of other hawks, though it is quite capable of doing so. Many adults take only birds in flight, but juveniles are less particular. Peregrines perfect their killing power by endless practice, like knights or sportsmen. Those most adaptable, within the limits of the code, survive. If the code is persistently broken, the hawk is probably sick or insane.

      Killing is simple once the peregrine has the advantage of his prey. Small, light birds are seized in his outstretched foot; larger, heavier birds are stooped at from above, at any angle between ten and ninety degrees, and are often struck to the ground. The stoop is a means of increasing the speed at which the hawk makes contact with his prey. The momentum of the stoop adds weight to the hawk and enables him to kill birds twice as heavy as himself. Young peregrines have to be taught to stoop by their parents; captive birds have to be trained by falconers in a similar way. The action of stooping does not seem to be innate, though it is quickly learnt. The ability to stoop at birds in flight was probably a comparatively recent evolutionary development, superseding capture by follow-chase and the taking of ground-game. Most birds still fly up from the ground when a peregrine passes above them, though this may increase their vulnerability.

      The peregrine swoops down towards his prey. As he descends, his legs are extended forward till the feet are underneath his breast. The toes are clenched, with the long hind toe projecting below the three front ones, which are bent up out of the way. He passes close to the bird, almost touching it with his body, and still moving very fast. His extended hind toe (or toes – sometimes one, sometimes both) gashes into the back or breast of the bird, like a knife. At the moment of impact the hawk raises his wings above his back. If the prey is cleanly hit – and it is usually hit hard or missed altogether – it dies at once, either from shock or from the perforation of some vital organ. A peregrine weighs between 1½ and 2½ lbs.; such a weight, falling from a hundred feet, will kill all but the largest birds. Shelduck, pheasants, or great black-backed gulls usually succumb to a stoop of five hundred feet or more. Sometimes the prey is seized and then released, so that it tumbles to the ground, stunned but still alive; or it may be clutched and carried off to a suitable feeding place. The hawk breaks its neck with his bill, either while he is carrying it or immediately he alights. No flesh-eating creature is more efficient, or more merciful, than the peregrine. It is not deliberately merciful; it simply does what it was designed to do. The crow-catchers of Königsberg kill their prey in the same way. Having decoyed the crows into their nets, they kill them by biting them in the neck, severing the spinal cord with their teeth.

      The peregrine plucks feathers from his prey before he begins to eat. The amount of plucking varies, not only with the hunger of the hawk, but also according to individual preference. Some hawks always pluck their prey thoroughly, others pull out only a few beakfuls of feathers. Peregrines hold the prey steady by standing on it, gripping it with the inner talon of one or both feet. Plucking takes two to three minutes. Eating takes ten minutes to half an hour, depending on the size of the prey; ten minutes for a fieldfare or redshank, half an hour for a pheasant or mallard.

      Prey may be eaten where it falls, if it is too heavy to carry off, or if it has landed in a suitable place. Many peregrines seem to be quite indifferent, feeding wherever they happen to make a kill. Others prefer a completely open place, or a completely secluded one. Seventy per cent of the kills I have found were lying on short grass, although most of the land here is arable. Peregrines like a firm surface to feed on. Small kills are often eaten in trees, especially in autumn. Birds reared in tree nests may eat their kills in trees whenever possible. On the coast, some peregrines prefer the top of the sea-wall for feeding, others eat at the foot of the wall, near the water line. The latter may have come from cliff eyries and be used to a steep slope above them as they eat.

      A peregrine kill can be easily recognised. The framework of a bird is left on its back, with the wings untouched and still attached to the body by the shoulder-girdles. The breast-bone and all the main bones of the body may be quite fleshless. If the head has been left, the neck vertebrae will usually be fleshless also. The legs and back are frequently left untouched. If the breast-bone is still intact, small triangular pieces will have been nipped out of it by the peregrine’s bill. (This is not always true of very large birds, which have thicker bones.) When a kill is left with a good deal of meat still on it, the peregrine may return next day, or even several days later, to finish it up. Surplus meat from abandoned kills helps to support foxes, rats, stoats, weasels, crows, kestrels, gulls, tramps, and gypsies. The feathers are used by long-tailed tits in the construction of their nests. I have found an unusual concentration of such nests in areas where many kills have been made.

      No other predator conflicts with the peregrine in the pursuit of prey, but it is sometimes prevented from hunting in certain places by the determined and concerted attacks of crows. When man is hunting, the peregrine goes elsewhere. It is remarkably quick to distinguish between an unarmed man and a man with a gun. There is a curious relationship between peregrines and kestrels that is difficult to define. The two species are often seen in the same place, especially in autumn and spring. I rarely saw one of them without finding the other close by. They may share the same bathing places, the peregrine may occasionally rob the kestrel of its prey, the kestrel may feed on kills the peregrine has left, the peregrine may attack birds that the kestrel unwittingly puts up for him. In September and October some peregrines seem to copy the kestrel’s way of hunting, and I have seen the two species hovering together over the same field. In a similar way, I have seen a peregrine hunting near a short-eared owl, and apparently mimicking its style of flight. By March the relationship between kestrel and peregrine has changed; the peregrine has become hostile, and will stoop at, and probably kill, any kestrel hovering near him.

      During ten winters I found 619 peregrine kills. Individual species were represented as follows:

      Woodpigeon – 38%

      Black-headed gull – 14%

      Lapwing – 6%

      Wigeon – 3%

      Partridge – 3%

      Fieldfare – 3%

      Moorhen – 2%

      Curlew – 2%

      Golden plover – 2%

      Rook – 2%

      In addition to these ten, there were 35 other species taken, to make up the remaining 25% of the total. Analysed by families, these are the proportions:

      Pigeons – 39%

      Gulls – 17%

      Waders – 16%

      Duck – 8%

      Game – 5%

      Corvids – 5%

      Small or medium-sized Passerines – 5%

      Others – 5%

      More woodpigeons were killed during the winter I have described in this book, because of their extraordinary abundance in the cold weather, and because of the absence of other inland species at that time. The relative figures for this particular winter are as follows:

      Woodpigeon – 54%

      Black-headed gull – 9%

      Lapwing – 7%

      Wigeon – 3%

      Partridge – 3%

      Fieldfare – 2%

      Moorhen – 2%

      Curlew – 2%

      Rook – 2%

      Mallard – 2%

      The remaining 14% was made up of 22 other species.

      These tables suggest that the juvenile peregrine preys mainly on those species that are most numerous in its hunting territory, provided they weigh at least half a pound. Sparrows and starlings are very common here, but few are killed by peregrines. Of the larger birds, the commonest and most widely distributed species are woodpigeons, black-headed gulls, and lapwings, in that order. If the total weight of available