POSITION OF LEGS OF BIRDS DURING FLIGHT. 143 



When travelling easily, however, it may tuck its feet comfortably 

 forward under its feathers. It was at St. Paul's Island, one of 

 the Pribiloffs, on the 21st of September, 1896, that I first had 

 my attention directed to this point. I was attracted by the sight 

 of a Black-legged Kittiwake (Bissa tridactylites pollicaris, Stej- 

 neger) flying with one leg hanging downward as if broken, the 

 other being concealed amidst the feathers. On looking closer at 

 several individuals which were flying about their nests, I found 

 that the legs may be carried in this species either bent forward 

 from the tibio-metatarsal joint, in which case the feet lie at about 

 the posterior end of the sternum, or they may be stretched out 

 straight backward, as in the larger Larus glaucescens, only they 

 do not reach so far as in that species, and the feet lie slightly 

 below the base of the tail. The first position appears to be that 

 of greatest ease for the bird. Both legs and feet are then com- 

 pletely hidden under the plumage, and their position can only 

 be ascertained by an observer who is near enough to note the 

 crinkle among the surface feathers at the place where each foot 

 lies concealed. The minute, however, the bird finds it necessary 

 to do any real work — as against the wind, in flying — it calls both 

 legs to its assistance by removing them from amongst the 

 feathers. Every intermediate position is used, and each foot 

 works independently of the other ; thus one leg may be packed 

 away, and the other hanging down straight as if broken ; or one 

 may be directed horizontally backward while the other hangs 

 down ; or again, both may hang downward as when just before 

 alighting. 



The above observation was only possible in an extraordinarily 

 favourable locality, where, as I crouched in close proximity to 

 their nests, the birds flew around quite near me. Later the 

 thought struck me that in my observation might be found the 

 explanation of the comparatively numerous Gulls which may be 

 observed in British waters, in localities where they are seldom 

 shot, with a leg hanging downwards as if disabled. It is seldom 

 easy to observe these Gulls closely, and my home is not at the 

 seaside. It was not then until July, 1899, that an invitation to 

 join my friend Mr. Henry Evans on a cruise in his steam-yacht 

 ' Aster ' gave me the chance for which I wished. I was then 

 able to definitely ascertain, that what I had observed in the Kitti- 



