POSITIONS ASSUMED BY BIRDS IN FLIGHT—BEETHAM. 439 
top of the column of rock, the base of which is vaguely suggested at 
the left-hand side of the print. Each time the bird approached its 
method was the same. It flew along the cliff-face until it reached a 
point nearly opposite to the nest, but considerably below it; then it 
swept round abruptly until it faced the cliff, at the same time giving 
its course a strong upward tendency, still trailing its feet. Plate 7, 
figure 1, shows the bird just after it had faced round to the cliff and 
was sweeping upward. As soon as it arrived directly opposite to its 
nest, its one thought was to stop the forward and upward impetus 
produced by the great soaring approach. 
Plate 7, figure 2, shows plainly the measures adopted by another 
bird—which, by the way, advanced in a more direct and horizontal 
course, and had, therefore, a more direct forward momentum to 
counteract. It flew straight for its nest, sweeping slightly upward 
until it found itself almost opposite the place, and perhaps some 5 or 6 
yards distant from it. Then by a dexterous turn it threw the plane 
of its great surface into a vertical position and at right angles to the 
direction of its course, thus offering the maximum amount of resist- 
ance possible. The whole area of the wings, body, and tail is directly 
opposed and spread out to resist the bird’s forward passage through 
the air, and it is interesting to note how the tail has been extended 
to the utmost, fan wise, so as to increase as much as possible the 
effective area. It will be noticed that the feet are thrust forward 
and the webs extended in anticipation of the coming contact. That 
a great strain is being placed upon the wings and that therefore a 
great resistance is being encountered is indicated by the curve of the 
primaries. 
Plate 8, figure 1, shows the position a moment later. The bird 
has now got its feet upon the rock (or rather one foot, for the other 
is thrust out horizontally on the nest, having no doubt missed its 
mark, and can be of little, if any, support), and appears to be almost 
stationary, but as a matter of fact it has still a forward impetys which 
the raised wings are trying to counteract. The bird has, indeed, 
just set foot upon the ledge, and is falling forward in the direction 
of its approach. 
The last photograph (pl. 8, fig. 2) again carries us on a brief moment. 
Now the bird has pitched forward on to its breast, its wings having 
failed to find sufficient resistance in the air to counteract the body’s 
momentum, and in consequence the wings have come crashing down 
upon the rocks at the end of their strenuous beat. The position of the 
tail is interesting; in plate 7, figure 2, it is seen fully expanded and 
depressed in order that its ventral surface may oppose the forward 
progress, and now it is turned upward above the back so that its dor- 
sal surface may find resistance and try to counteract the tendency 
to pitch forward on to the breast. 
