HOW BIRDS JOIN THE R.F.C.

Otago Witness, Issue 3332, 23 January 1918, Page 62

HOW BIRDS JOIN THE R.F.C.

" The increasing importance of the study of biri fiignt is revealed m the tactics of the flying men who have wrested command or tne air irom the Zeppelin. " The Zeppelin cannot noid the air. It yields to the aeroplane properly manoeuvred. Ihe manoeuvre is based on bird flight." Such are the conclusions of a writer in London Nature. They are confirmed by the observations of Bentley .. Beetham, F.Z.S., a high authority upon the movements of birds. The aviation of the immediate future, he declares, will be based upon the study of the positions assumed by birds in flight. " Even should man eventually master the art of aerial navigation so thkt it is rendered as easy for him as terrestrial locomotion, birds would, says Professor Beetham, by reason of their facility in estimating air currents, still remain vastly his superior in the art —if not in actual pace, at least in the finer manipulations. It requires . a certain type of physical organism to make an aviator. One must have the bird nature. A gymnastic instinct is necessary, an ease in tne imitation of bird movement, a certain intuitive perception of what the wing is to the bird and of how the tail steadies and directs. Without this equipment there seems little hope for an aviator. "To .gain the velocity in order to create the resistance necessary for the support of all ' heavier-than-air' machines, some birds run or swim, others simply spring into the air and. by tho vigour of their flapping achieve the same result, while others again launch themselves from some advantageous point—a tree or rock—and in falling gain the desired resistance, as Professor Beetham says in ' British Birds.'

"These are the motions to be followed by the flying man instinctively, his machine being to him what the wings and tail are to the bird :

" Stepping to the cliff edge, and if there is no cause for undue haste, having raised and partly unfolded its wings, the bird prepares to dive into space. This dive, it should be noted, is not directed downward, but rather as horizontally outward from the cliff as may be (sometimes it appears to have even an upward tendency). If the bird is one" possessed of broad large wings not much altitude is lost, and it ekims through the air. in much the same fashion as does a piece of cardboard thrown horizontally. If, however, as in the case of auks, the wings are small and narrow and the body heavy, then the bird at first drops nearly vertically, only being able to gain a more horizontal course as its velocity increases.

"Sometimes birds of this latter class, presumably through misjudgment of the space they have to work in, do not got the horizontal course in time, and crash into the rocks or sea at the foot of the cliff. This is very noticeable when a group of cofins hurriedly takes flight from steep boulderstrewn slope. In these circumstances I have frequently seen quite a number of birds come to grief on the rocks within 30 yards of starting. Most_ of these', though somewhat dazed by the impact, flutter and claw their way on to the top of some big boulder, and after a moment s pause again dive forth, but not infrequently with no better result. The first failure is, I believe, often caused by their paying too much attention to and looking behind at whatever startled them, instead of gauging their proper angle. "The raising and unfolding of the wings is worthy of a little consideration. The former usually takes place not after, but previous to, the diving or springing forward, while generally the whole 'foot' is at rest upon the rook. Of course, when suddenly alarmed bird's sometimes cast themselves from the cliff _ without first raising their wings, and in consequence fall rapidly. "The old idea that the wings of a bird simply flap up and down and that by some means the body travels steadily along on a level horizontal course has had to h*» given up. The aviator must be guided accordingly, difficult as it may be 'for him to realise that at each beat of the wing of a bird the body is raised as well as propelled. In the bird's flight the wings are raised and .the body seems to be dependent; from them, and yet again the wings are far depressed and the body appears to be pushed up and supported by them."