ICO Mattinglev, Principles Governing Movement \^^^ "t"„ 



imitation, &c. When birds like our Mapgie [Gymnorhina tibicen) 

 build nests of wire ; when birds use boxes prepared for them 

 to nest in ; when our Ravens rob the nests of other birds ; when 

 birds feed in the open mouths of crocodiles, and also on the backs 

 of cows ; when the Parrot of New Zealand {Nestor notabilis) took 

 to killing sheep ; when birds nesting on a firm or stiff bough 

 build a shallow nest, and when on a swaying limb they build a 

 deeper nest, or when they build floating nests to rise and fall with 

 the level of the water ; when our Lyre-Birds {Memira victoria) 

 imitate human and other animal sounds, &c. — can we call these 

 few of many illustrations instinct ? Quite erroneous ideas are in 

 circulation. It is said that young chickens, when they have 

 developed to their full size in the egg, break their shells, quit them, 

 and at once stand on their feet, run, and peck grain and insects 

 from the ground ; thus arises a whole series of complicated notions, 

 directed to a certain aim, without any teaching, example, or experi- 

 ence coming in. Just the same story is told of young Ducks, which 

 in addition give an especial proof of instinct in that as soon as they 

 leave the egg-shell they run to the water and swim about therein. 

 This last feat is said to be done by young Ducks hatched under 

 hens, which therefore cannot be led to swim by any maternal 

 allurements, and the poor foster-mothers are said to stand in 

 despair because they see their nurselings torn from their protection 

 and are not able to follow them. This all seems so natural 

 that it is generally accepted without demur, and would indeed, 

 were it true, scarcely seem to leave doubtful the existence 

 of instinct in the earlier accepted sense. But in reality matters 

 are very different. That which occurs immediately before the 

 escape of the chicken from the egg does not depend on the indepen- 

 dent action of the young bird, but takes place in quite mechanical 

 fashion, as Professor L. Biichner puts it, and as the result of a 

 series of unconscious movements, which are caused by the fact that 

 from 24 to 34 hours before hatching the chicken begins to breathe, 

 and at last requires more air than can pass through the shell. 

 Hence arises a great danger of suffocation, and in consequence of 

 this a strong reflex action takes place, by means of which the chick 

 is caused to strike or push violently against the inner wall of the 

 shell with a sharp bony point formed on the beak and known as 

 the egg-tooth, and the whole body is stretched and extended. 

 Pressure is caused by the natural growth of the body within, and 

 the breaking of the shell cannot long be delayed. But when the 

 chicken is out of the shell it is far from running about and picking 

 up corn. It generally lies for about two hours helpless on its 

 stomach, and neither eats nor pecks, even though a grain of corn 

 be placed in its beak. It then begins to make feeble attempts 

 to move, in which it at first uses its wings just as though they were 

 crutches. It gets up, falls down, gets up again and again falls 

 down, and gets up again, so that its motion looks more like slipping 

 than running. If a noise is made near it — for instance, if anyone 

 knocks a table with the finger — it turns to the side of the noise, 



