There is a theory that the eyes of wild creatures magnify things seen,
so that they appear many times larger than to human eyes. This has
been held to explain why creatures smaller and weaker than man, like
hares and rabbits, flee desperately at his approach--a reasonable habit
if all men to them are as giants. One's sympathies would go out to the
rabbit if he sees foxes as horses, and weasels as foxes. If birds' eyes
have magnifying power, many miracles of flight and of feeding would
seem natural. The swift passage of birds through obstacles that appear
to our eyes to be almost impenetrable is something of a miraculous
nature. Without a moment's survey of difficulties or direction, a bird
flashes through a jungle where there is no possible way for it to be
found by human eyes. The blackbird flies shrieking in and out of a
dense hedge of thorns; but not a feather is ruffled in the course of
his intricate flight. Or watch the jay or the sparrow-hawk passing at
speed through an almost solid network of twigs and stems. The human
eye cannot properly follow this performance by the sparrow-hawk; a
swish and a streak of bluish grey, and it is gone. Many a bold jay,
finding itself caught between beaters and guns, has saved its life by
this wonderful power of flight at speed, going away without giving the
slightest chance for a shot; it will dash out of a wall of undergrowth
on one side of a ride sheer into another wall. No doubt the jay knows
to an inch which is the shortest cut out of man's sight. Hardly less
wonderful than birds' flight through crowded obstacles is the way in
which rabbits scurry and twist through masses of fern and brambles.
But where the theory of eye magnification would seem most probably true
is where tits and goldcrests are searching for food on the underside of
fir boughs, and finding food which no man's eye could see unaided.
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