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The Peregrine: The Hill of Summer & Diaries: The Complete Works of J. A. Baker
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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.
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