. Animal flight; a record of observation . for gliding in this way, , ina more or less straight line, with the wings at maximumcamber, with or without gain of height. The distancesthrough which a birdmay lift-glide varyfrom a few metres toone or two hundredmetres. At the endof a lift-glide thebird usually beginscircling. In rare cases,if it reaches more soar-able air, it may flexits wings and flex-glide up - wind athigher speed but withno gain of height. Fig. 13. 10th Jan., Jharna Nullah.—Vulture ease-gliding, andthen flex-gliding in a strong wind. In lift-gliding the bird usually shows at
. Animal flight; a record of observation . for gliding in this way, , ina more or less straight line, with the wings at maximumcamber, with or without gain of height. The distancesthrough which a birdmay lift-glide varyfrom a few metres toone or two hundredmetres. At the endof a lift-glide thebird usually beginscircling. In rare cases,if it reaches more soar-able air, it may flexits wings and flex-glide up - wind athigher speed but withno gain of height. Fig. 13. 10th Jan., Jharna Nullah.—Vulture ease-gliding, andthen flex-gliding in a strong wind. In lift-gliding the bird usually shows at intervalssmall rotations to and fro round the dorso-ventral this phenomenon is due to this form of flightbeing, for some unknown reason, necessarily unstable,or on the other hand the instability is due to somedefect in the air in which the bird finds it necessaryto lift-glide. Observation of cases of stable lift-glidingappear to point to the second alternative as being moreprobable, as will be described in a later
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectan, booksubjectflight
