Page:Popular Science Monthly Volume 77.djvu/144

138 by students in recent years, by the Hampton Court maze or labyrinth method, upon young chicks, and various wild species, show an ability to learn more or less rapidly, according to the simplicity of the path to be traversed. They always seem to be guided in large measure by sight. Their educability has been further tested by Thorndike and others, by placing food within sight, but enclosed in a wire box, access to which can be reached only by working some simple contrivance, with bill or foot, such as pecking or pulling at a string. The animal is thus induced to do an unusual thing, or to do it in an unusual way, but some species, like the house sparrow, have proved apt to learn, and though success may come first through accident, by the tenth or some later trial, the new act is learned, and unnecessary movements are in time eliminated. The effect of the acts performed, as in the case of exit from the labyrinth, is remembered for days or weeks, according to the strength of the habit, or the ability of the learner. Whether the memory involved in these and similar acts is of a visualized character, involving a memory idea, image or picture, may be doubted, though Edinger among others is not inclined to admit this. We might ask why a bird, with a memory image of the position of her nest, does not always strike a direct path to it, after reaching her tree. Why should she slavishly follow the track stamped in by previous associations, walking along a certain branch, and grasping a certain twig, before landing at the nest-side, a practise very commonly followed? Such behavior certainly can not always be attributed to the inhibitory effect of fear.

All the intelligence which birds may on occasion exhibit seems to give way under the spell of any of the stronger instincts, as when the male canary, as related by Blackwell, plucked the feathers from the necks and backs of its own young in order to line a newly built nest, although ether feathers were supplied to it in abundance. They seldom meet emergencies by doing the intelligent act, and, in spite of the anecdotes, probably but seldom come to the effective aid of their companions when in distress. On the other hand, I have more than once seen a mother bird try to pluck a hair or piece of grass from the mouth of a nestling.

It has been asserted that only birds can be frightened from fields by scarecrows, but to most birds any strange object is a "scarecrow," which may in time, and often brief at that, become familiar through association, as shown by the many devices used by farmers to frighten crows from their fields of newly planted corn. The genuine scare crow is a subject worthy of further study.

At this point I wish to notice certain anomalous actions of peculiar interest in birds, and to refer particularly to the wood swallows (Artamidæ) of Australia, the hornbills (Bucerotidæ), of the East Indies, and to the honey-guides (Indicatorinæ), of the East Indies and Africa.