Some Flying Magicians

New Zealand Herald, Volume LXXIII, Issue 22350, 22 February 1936, Page 31 (Supplement)

Some Flying Magicians

JNSTINCT in the case of animals is an« unfathomed mystery. One naturalist has stated that the word "instinct" is really a cloak for our ignorance, writes Oliver G. Pike, F.Z.S., in a London journal. Look at some of our birds and the way they construct their homes. It would puzzle the cleverest humans to make a home in a tree-top which would withstand the gales of many seasons. But the rook and crow, with their beaks alone, will put together a number of twigs in such a manner that they will remain in the highest branches to be swayed by the merest breeze, or thrown about by the fierce storms of winter. A young rook building its first nest will construct it with as much skill as the oldest bird. The diminutive long-tailed tit makes a nest of moss, rabbits' fur and lichens; it is a wonderfully-built little home. It is sometimes oval, at other times as round as an orange, with an interior about the size of a tennis ball. We can understand a bird putting together a mass of moss and other material, then going inside and working its body about until a space large enough for the rearing of the young is made; but this tiny bird works quite differently. The foundations are first fixed to the branches, then the birds work upward, building the sides and the round interior as they progress. The whole thing has to bo carefully thought out, but

as the work proceeds a small hole is left as an entrance on one side near the top. The roof is built, and the result is one of the most perfect nests in the world. Some of the most wonderful specimens have been built by tits that have not nested before, and never had a lesson. Last summer a leaf-cutting bee entered my greenhouse and set to work on the fuchsias. This ii..->ect, for the construction of the little home in which it deposits its eggs, requires eleven pieces of green leaf. It cuts these with uncanny precision, for all the pieces, each of a different shape, must fit together with perfect joins. When cutting the leaf with its powerful jaws, it sits on the piece to be removed, and at the moment when we think leaf and bee will fall it vibrates its wings, finishes the cut, and flies off with the severed portion. This is joined up with the previous piece in some small tunnel or crevice. Those common insects known as weevils are really tiny beetles. When the female wishes to lay her eggs, she selects a leaf growing on a tree, and near the part attached to the twig she makes a cut from the mid-rib to the outer edge. Going again to the centre, slio makes another cut on the corresponding side, then rolls the two parts together until thoy resemble a cone. If wo examine a number of these we see that the portion which is cut near the base of the leaf is the same shape in each instance. Mathematicians have proved that the curves which the tiny beetle cuts with its jaws are those which allow for the most perfect rolling of the loaf.