BIRDS IN FLIGHT

New Zealand Herald, Volume LXXII, Issue 22197, 26 August 1935, Page 15

BIRDS IN FLIGHT

MASTERY OF THE AIR EXPERTS STILL PUZZLED RELATION TO AVIATION The various factors contributing to the mastery of flight by birds are still a matter of investigation by authorities, who have as yet failed to elucidate several important points which might lead to a complete understanding. This was .one of the points made by Mr. R. A. Falla, ornithologist to the Auckland War Memorial Museum, in a lecture delivered yesterday afternoon under the auspices of the Auckland Institute and Museum. There was a large attendance. Those fortunate enough to enjoy ocean voyages, said Mr. Falla, must have been impressed with the assurance of an albatross in its steady and smooth flight astern of a vessel, even under rough weather conditions. The albatross would glide, a simple form of bird flight, but the necessary velocity for the achievement of the glide had to be obtained by a primary beating of the wings. However, if the wind were strong, the bird might turn about and face it, spread its wings, use its large feet practically to "run" across the water in the face of the wind, and so gain impetus for flight It was a source of wonder how birds could glide for an almost interminable time without apparent effort. The gliding flight of birds was a fruitful source of study to students of early aeronautics, who obtained valuable data concerning the relationship of wing area to the weight of the body. But other factors appeared during the evolution of aeroplane design, which necessitated a departure from the study of birds. As distinct from gliding, the flapping flight, with moro complicated action, was adopted by birds, the wings making very much the same movement as an oar, Mr. Falla added. At the top of the stroke, the wing tip was well back, and there was a long forward movement in which the wing almost gripped the air. Then there was the soaring method of flight, which few birds were capable of accomplishing, and in which altitude was gained without any visible motion of the wings. While some birds soared with the assistance of upward air currents, others apparently did this with their own efforts, a fact which intrigued and somewhat puzzled observers. Feathers served as a splendid insulation by which birds retained the intense body heat necessary for a highly charged system of muscles and nerves. Feathers were a definite contribution, to the art of flight. The better to fly, birds had been given the beauty of streamline form, and a fine example of this was the sea swallow. Nature had provided certain birds with special wing formations to facilitate hovering, and one of these was the humming bird, but its wing movements were too rapid to record by the slow-motion camera.