GLIDING AMONG THE VULTURES

Hawke's Bay Herald-Tribune, Issue 142, 3 July 1937, Page 11

GLIDING AMONG THE VULTURES

Their Habits in the Air

j HAVE just returned from.a business trip to Johannesburg^ on whieh I was fortunate enough to be able to taka with ma a Kirby K-ite eailplane, writes Plilip Wills. in • the Listenen This Is the first time in which a soaring expedirion abroad has been • made by say but the Gqrm'ans, and I was able to do something to dispel the general belief overseas that tbey ara- the only eountry knowing anything about soaring. They had never seen any thermal soaring out there — that is, advancing by using currents af rising warm air caused by -the sun's heat on warm days — and I did sevcral thermal flights, on one of which I reached a heiglit of 5400 feet above the start, or 11,200 feet above sea level. The most intercsting discoveries I made, from-the general point of view, were regarding the methods of the vultures out there. The vulture has to f&ee a problem very similar to that of the soaring pilot. He is a large and heavy bird, and he hae to be on the wing all day and every day. Ha can't be a very efficient soaring shape, becanse if you maka yourself a supersoarer you become very bad at take-, offs and landings. This is wh'y the albatross, the most efficient soarer in the world, has to Iimit himself to the latitndes known as the Eoaring Forties, where there 5s always a wind to help hrm to take off. On the land, or on a cairn day, an albatross simply can't get off the ground at all. But tho vulture has to take off from the liigh veldt, six thousand feet up, and the air is still forther Tarefied by the heat. The solution he has arrived at is to go in for thermal soaring and so make use of the great numbers of rising columns of warm air which are found in tsubtropical countries} and which make things 80 very uncomfortable for aeroplanes and so lovely for sailplane pilota. Tho vultures parcel out the air into aTeas about half-a-inile square, and bird A patrols his own territory, keep-

ing a sharp- watch on neighbours B, C and T>. They are on the look-out for two things—- food, and a free lift from thermals. Suppose A suddenly spots a kill below.' He hovera and dives down at it. , Instantly B, 0 and D dash in, and 'their neighbours follow suit. As everybody knows, immediately an animal dies, tho air becomcs full of vultures, and this is how it is done. But now suppose our friend A discovers a thermal. Immediately he enters the rising air he starts to circlc and climb; this is the signal for his neighbours, and in less than a minutc he is the apex of a pyramid of wliecling and elimbing vultures. Of cou^se, I made'much use of this; wHenever I saw a number of birds in a thermal I would fly over and join thcm. They were not in the least frightened, as they have no natural enemies in the air. What waa unexpected, howevcr, was that I found it was no one-sidcd arrangement in my favour. When 1 joined the soaring brigade I was acceptcd eilently into the ranks. If I gatecrashed into A's territory, he simply moved one aTong to B, B presumably moved over to O, and so on perhaps doim tp the coast? four hundred xniles away. "When I saw A circling, I would go and join liim, But if I found a thermal on my own, in Ies3 than a minute there would be a swish and a large brown bird with a wicked face would como wliizzing in and join ino, and in no time I would bo one of half-a-dozen or more birds, wheeling so close that - 1 could sometimes see their eyos. If the thermal went high er" than about 2500 feet, tlie birds would usually leave me. Evidently their comfortable range of vision is ahout 2500 feet, or half-a-imle; th'ough one aeroplane pilot told me hc had met a vulture at 10,000 feet. If I had pnshed my stick forward and pnt my machinc into a dive, I'm sure that in no time I would have had a train of shrieking birds on my tail looking for an imagined kill.