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 prey is considered, the woodpigeon probably represents a proportion of the total biomass approximately equal to the percentage of woodpigeons actually killed by the peregrine. The method of selection employed, if there is one, may in fact be nothing more spectacular than this: that the peregrine kills most frequently the species of bird it sees most frequently, provided it is a reasonably large and conspicuous one. The presence of abnormally large numbers of any species of bird invariably results in a higher proportion of that species being killed by the peregrine. If a dry summer enables more partridges to breed successfully, then more partridges will be taken by the peregrine during the following winter. If wigeon numbers increase when the cold weather comes, more wigeon will be killed. Predators that kill what is commonest have the best chance for survival. Those that develop a preference for one species only are more likely to go hungry and to succumb to disease.
Over the valley and the estuary, many gulls and lapwings are killed by the peregrine in October and November, chiefly from freshly ploughed land. From December to February woodpigeons are the main prey, especially in hard weather, when fewer lapwings are available. Woodpigeons are still taken in March, the killing of lapwings and gulls increases again, and more duck are killed than in any other month. Game-birds, moorhens, fieldfares, and waders,