228 THE STRUCTURE AND LIFE OF BIRDS cuap. 
I think, least of all. The pelican’s flight I do not 
know, but the rest ascend by a comparatively gentle 
gradient ; some of them even require the help of a 
head wind, if the ascent is to be made with reasonable 
ease. The cormorant, when he leaves his fishing, 
struggles hard before he gets clear of the water, 
advancing quickly but ascending slowly, a striking 
contrast in every way to the skylark as he mounts 
lightly to the upper air. 
Downward Flight. 
It is a beautiful thing to see a pigeon, with wings 
partly flexed, glide downwards through the air, then, 
as he nears the ground, suddenly give his body an 
upward instead of a downward slope, spread his wings 
to stop himself, and, with all the grace of the “ Herald 
Mercury,” alight. 
The suddenness of the change from horizontal or 
upward to downward flight is very striking. It is often 
maintained that it is due to a shifting of the centre of 
gravity by the elongation of the neck or of the legs, or 
by some of the other little manoeuvres known to birds, 
which have this object. But the pigeon has no length 
of neck or legs to extend. Ifyou watch him change 
all at once the incline of his body, you will see no 
working of either. The very quickness of the move- 
ment shows that it must be due to muscular action, 
and it is no doubt the work of the muscle called the 
‘Latissimus Dorsi, which in horizontal flight raises the 
hinder quarters by hauling upon the wings and which, 
as I have shown, probably helps in the process of 
breathing (see p. 89). 
