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Are Birds Deceitful ?



Eggs deposited in nests on or in the ground, or among pebbles

or ground litter, are usually mimetic in colouring and extremely

difficult to distinguish from their surroundings; but unhappily they

are more liable than those built higher up to destruction by stoats

and other ground-frequenting vermin.


It is extraordinaay how men who become obsessed with a

theory will try to strain every known fact into its service. The fact

that the egg of our common Cuckoo not infrequently resembles the eggs

of its foster-mother is assumed to be with the object of deceiving

her ; but when we know that by far the greater number of Cuckoo’s

eggs in no wise resemble the eggs among which they are deposited,

this notion at once disproves itself. Nobody really knows why some

Cuckoo’s eggs are such admirable copies of those with which they

are placed, but it has been suggested that if a Cuckoo is reared by a

Hedge-Sparrow or any other bird, she will probably lay in the nest

of that bird, and that similar feeding for many successive generations

may affect the colouring of the eggs. I don’t know; and that is

about as far as most of us will ever get in explaining many of

Nature’s secrets : and if the truth is ever revealed, we shall discover

that many of the explanations suggested are miles away from it.


Doubtless many of our members have observed, as I fre¬

quently have done, that, after a flight many birds did not return in

a straight line to their nests : a Blackbird or Thrush, if its home is

situated in ivy or thick scrub on one side of a wall or fence, usually

flies straight over in a straight line past its nest, and at a little

distance beyond it and then turns and slips quietly back under cover.

A Lark descending from an aerial flight alights on the ground at a

fair distance from its nest and wanders, apparently in an aimless

fashion, among the herbage with many turns and twists, but always

approaching more closely to its objective until within about a foot

of it, and then attains it at a run : doubtless the object is to deceive

the watcher; but probably this habit has become instinctive and

the deception is unconscious, just as dogs descended from a wolf

stock approach their masters in a wide half circle, as Darwin points

out and as I have repeatedly noticed: the original purpose pre¬

sumably was to avoid a frontal attack from an adversary.



