With the noble peregrine a diminishing frequenter of rugged cliffs and mountains, the nimble merlin an inhabitant of open moorland, and the hobby an infrequent summer migrant, the only British falcon widely seen and known is the one most un-falconlike in behaviour, the kestrel.
Because it obtains most of their prey, not following a high-speed chase and headlong stoop, but with a sudden plunge following a leisurely scanning of the ground from the series of winnowing surveys from high above, interspersed with frequent static hovers when some slight movement on the ground demands closer scrutiny, its mode of hunting attracts attention. Furthermore, even though it can achieve coastal or mountain haunts as remote as the ones from the peregrine, it is also equally in your own home over farmland or town.
Most farmers realize its value like a mouser, and since it’s less vulnerable to hunt in woodland it’s never been persecuted by gamekeepers to the same extent as the sparrowhawk. Therefore, until quite recently, not just its conspicuous aerial habits, but additionally its abundance as a whole numbers, managed to get an almost everyday bird for most countrymen and never a few townsmen.
Within the last three or four years there’s been an alarming decline in kestrel population, probably attributable to the utilization of poisonous pesticides. It had been notable that after this decrease was initially evident over the mainly arable (or horticultural) south-eastern 1 / 2 of England, kestrels remained as as fashionable as formerly in coastal regions of the west and south-west, where mice and beetles were up to now untainted with organic chlorine poisons.
The kestrel must surely be the origin of the expression ‘eyes just like a hawk’ as a simile for keenness of vision. To determine a kestrel hovering on the hundred feet high over a grassfield, then plummet right down to a kill with extended foot-and then, as the prize is come to a nearby fence-post, to find out through binoculars that the prey was just a beetle about half-an-inch across, although somewhat of the anti-climax to the excitement of the proceedings, is nevertheless the truth of the telescopic powers of vision possessed with this bird.
The old names of ‘wind-hover’ and ‘stand-gale’ with this falcon suggest a comprehension of the actual mechanics of their hovering technique; even though this is an over-simplification of what actually occurs, basically ‘standing still’ in the air is achieved by regulating the speed of flight to complement exactly the speed of the wind so it faces. Presumably a kestrel could be unable to hover inside a complete calm; presumably also, the air isn’t in this motionless state, so the difficulty never arises.
Although the kestrel is generally seen in typical hunting flight-alternately flapping for some beats after which gliding or hovering-it may, specifically in late summer or early autumn, be observed high and flying on the direct course, when it might be mistaken for any peregrine.
It is known that some young kestrels move southward at the approach of the first winter, and also, since such stray birds are most frequently observed flying southwards (not infrequently in colaboration with swallows) these pseudo-peregrines are assumed to become birds within this category. A fascinating point which ringing of young kestrels, and subsequent recoveries, has revealed, is the fact that out of one brood, one bird might be such a winter emigrant, moving some countless miles to the south, while another can always be inside a few miles of their home during its first winter.