MIGRATORY BIRDS IN ACTION

New Zealand Herald, Volume LXXV, Issue 23145, 17 September 1938, Page 1 (Supplement)

MIGRATORY BIRDS IN ACTION

Mystery of the Flights

By KOTARE

THE return of migratory birdf brings us no nearer a solution of the mystery of their certain flight through the boundless sky* Theories there are in abundance, but none that commands universal acceptance. In their season they come; in their season they go. In Europe where the land masses are large and the intervening seas narrow an instinct for food and warmth' may explain much. The land is for many birds never out of sight. But here in New Zealand these relatively small islands are set in an infinity of wild waters. There can be no remembered landmarks, no guidance through the eye. The Maori solved the problem of the cuckoo's disappearance by presuming a .periodic adoption of reptilian form. The bird went to the ground, to take the air again when the time was ripe. Our wider knowledge and perhaps our lack of poetic vision make us seek a more scientific explanation. But the ultimate mystery remains—the why of the birds' knowledge, and the how of his miraculous achievement. The American poet Bryant solved the problem this way: There is a Power whose care Teaches thy way along tha pathless coast— The desert and illimitable air— Lone wandering', but not lost. But science wants to_ know more than jthat. Our migratory birds do not come over land; so the pathless coast and the desert do not come into ture. Apparently the birds do not jpome or go alone. They do not wander,'but move steadfastly to some clearly realised objective. We hear a few. stray voices among the familiar bird songs, and we know they are here. For a few months we take them for granted, .Then the old birds alone remain and the visitors are gone till next spring brings them back. Communicating Ideas There arises, too, this additional problem. How do the birds act in unison? How do they communicate with one another so that they can act in concert in so vital a matter? Either, there must be a common urge that expresses itself in exactly the same actions in all the individual members of the species, or there _nru_st be some means by which that initial impulse is united into some sort of mass-mind which enables .all the smaller groups to act as parts of a vast army moving in cohesion to a definite goal. If animals communicate thoughts or feelings or purposes how do they set about it? Naturalists in England have been studying for many vears the concerted actions of such birds as the starlings. They are migratory in the northern hemisphere. The investigation into the incidence of the dreaded foot-and-mouth disease which spreads appalling devastation among English ' farm animals is pointing to the starling as the villain of the piece. No matter how carefully preventive measures are adopted in England nothing seems able to keep the fell disease out of the country. New infection is continually arriving. The present idea is that the starling puddles around in infected areas in European countries, and within a few hours is shedding the collection of germs nestling about his feet, on English pastures. What Observers Record It sounds feasible and it eliminates afc' least one possible source of the disease in New Zealand. It also ■ suggests a possible means of the transference of other plagues and pests to our land. But the starling is perhaps our best example of familiar birds that opera to in large masses and express in their united actions a common purpose carried out with the precision of a carefully drilled Prussian army. This is how different observers have described the mass movements of the starling. First there is that careful observer W. H. Hudson: "If a sparrowhawk made its appearance, instantly the crowd of birds could be seen flying at furious speed toward the nearest flock of sheep, and down into the flock they would fall like a shower of stones, and instantly disappear from sight. There they would remains on i. the ground among the legs of the grazing sheep until the hawk had] gone on its way and passed out of 3sight." The whole defensive measure-was undertaken in a flash, the plan of campaign decided on and communicated to the whole group before a human mind could have focussed the coming danger, and the combined action undertaken at high speed without the slightest trace of confusion. Francis Pitt, a noted authority on natural history, thus describes the starlings' massed attack on the roosting place: "A single starling flew over to be followed by a party of six and then se%*eral small parties came along. Next a flock of a hundred or so arrived. Then came other flocks, and at last a really big flock came up to wheel above the wood and meet the other flocks in mid-air." From all points of the compass the birds came, the one common purpose bringing them to the rallying place at the same time. The Common Mind "It was now a great dark cloud swinging and turning in vaporous undulations, vet getting more vast each second. Whether there is any such thing as thought transference or mind waves I do not know, but the way in which that vast concourse of birds manoeuvred and turned without collision or mishap, as if indeed the individuals were lost in a single mind made us less sceptical on the point than we had been." Douglas Gordon, the leading authority on the fauna of-the Devon moors, is perplexed by the same phenomenon:' Perhaps the most remarkable example of bird telepathy is provided by a great flock of starlings coming in to roost. The dusky column of birds describes a long curling sweep across the darkening sky, circles the roosting-place, once or half a dozen times as the case may be, then at the psychological moment descends like a falling cloak upon the gloomy tangle of tree-tops. The actual descent constitutes one of the most extraordinary aerial evolutions that, can be witnessed. As often as not the wheeling flock breaks 'in _ mid-career into a dizzy cascade of birds plunging headlong into the dark evergreens with a sound as of waves on shingle." Who or what decides the exact moment of that massed plunge? Who or what appoints for that particular evening that special roosting-place out of several in use? Are there leaders that make the decisions? It is not likely, and there is too'much noise to let any audible signal be heard above the clamour. Whv should a "mighty avian company move like one bird, not a single individual among thousands appearing to entertain the slightest doubt of the next move?" They keep perfect order, wheel together without confusion, rise and fall in complete unison. The fact is, we know practically nothing yet of bird psychology. Something beyond our ken at present is working in the bird mind. An idea is formed and communicates itself to the whole mass, forging it for the time t into a purposive unity. But how it as don the higher mind of man cannot erea guess.