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It is undeniable that strong impressions upon the sense of sight, affecting the parent during conception or an early stage of pregnancy, may and do influence the formation of the embryo, and it has consequently been asserted that the sight of the eggs lying in the nest has such an influence on the hen Cuckoo, that her egg, which is ready to be laid, assumes the colour and markings of those before her. This is not, however, supported by facts, for the egg of a Cuckoo is frequently found with eggs which do not in the least resemble it (e.g. those of the Hedge-Sparrow); or with eggs which, from the nature of the nest, could not have been seen by the Cuckoo (as in the case of the Redstart, Wren, or Willow Wren); or deposited in a nest before a single egg had been laid therein by the rightful owner. Again, two Cuckoo's eggs of a different colour have been found in the same nest. If both were laid by one bird, we have a proof that the same Cuckoo does not always lay eggs of the same colour; if laid by different birds, then the Cuckoo is not so impressionable as has been supposed.

What really takes place, I believe, is this :—

The Cuckoo lays her egg upon the ground; the colour of the egg is variable according to the condition of the ovary, which depends upon the age of the bird, the nature of its food, and state of health at the time of oviposition. With her egg in her bill, the bird then seeks a nest wherein to place it. I am not unwilling to accept the suggestion that, being cognizant of colour, she prefers a nest which contains eggs similar to her own, in order that the latter may be less easily discovered by the foster parents. At the same time the egg in question is so frequently found amongst others which differ totally from it in colour, that I cannot think the Cuckoo is so particular in her choice as Dr. Baldamus would have us believe.

The manner in which "the cuckowe's bird useth the sparrow," "oppressing his nest,' living upon him, and finally turning him adrift, has furnished a theme for poets and prose writers in all ages, and has awakened in no small degree the speculative powers of naturalists.

The story is as old as the hills, and it would probably be difficult, if not impossible, to trace

it to its origin. It was known to the ancients that the Cuckoo leaves its eggs to be hatched by other birds, but they mingled fact with fable, believing, or at all events asserting, that the young Cuckoo devoured not only its foster brothers and sisters, but ultimately its foster parents. Hence the expression which Shakespeare put into the mouth of the Earl of Worcester to the effect that the youngster

"Grew by our feeding to so great a bulk

That even our love durst not come near his sight
For fear of swallowing."-Henry IV. act v. sc. 1.

But though so time-worn is the tale as to be very generally believed, it is singular how few writers have attempted to show a foundation for it from their own observations. So scattered, indeed, is the evidence on the subject, that many naturalists of the present day still hesitate to believe the story, pronouncing the alleged feat of strength on the part of the young Cuckoo to be "a physical impossibility."

Although my present purpose is to direct attention to the latest observations upon this vexed question which have come to us with

authority, it will not be superfluous to glance very briefly at what had already been advanced in support of the statement referred to.

The

Dr. Jenner says positively ("Phil. Trans." vol. lxxviii. p. 225):-"I discovered the young Cuckoo, though so newly hatched, in the act of turning out the young Hedge-Sparrow. little animal, with the assistance of its rump and wings, contrived to get the bird upon its back, and making a lodgement for its burden by elevating its elbows, clambered backwards with it up the side of the nest till it reached the top, where, resting for a moment, it threw off its load with a jerk, and quite disengaged it from the nest. It remained in the situation for a short time, feeling about with the extremities of its wings, as if to be convinced whether the business was properly executed, and then dropped into the nest again."

Montagu, in the Introduction to his "Ornithological Dictionary," states that he took home a young Cuckoo five or six days old, when, to use his own words: "I frequently saw it throw out a young Swallow (which was put in for the pur

pose of experiment) for four or five days after. This singular action was performed by insinuating itself under the Swallow, and with its rump forcing it out of the nest with a sort of jerk. Sometimes, indeed, it failed after much struggle, by reason of the strength of the Swallow, which was nearly full feathered; but, after a small res-pite from the seeming fatigue, it renewed its efforts, and seemed continually restless till it succeeded."

Mr. Blackwall, who published some observations on this point in the fourth volume of the "Manchester Memoirs" (second series), says that a nestling Cuckoo, while in his possession, turned both young birds and eggs out of its nest, in which he had placed them for the purpose. He further observed "that this bird, though so young, threw itself backwards with considerable force when anything touched it unexpectedly," an observation subsequently confirmed by Mr. Durham Weir in a letter to Macgillivray.1

1 "Hist. Brit. Birds," vol. iii. p. 128.

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