THE TUBE-NOSES 1 79 



overtaking it too quickly only when it is steaming against the wind 

 because their 'ground' speed is then reduced by the speed of the wind, 

 but they move too fast when a ship is steaming with the wind and 

 must then make a series of ellipses far out to port and starboard if they 

 would keep with the ship. In calm weather these long-winged petrels 

 manoeuvre in all directions and their true flight-speed, estimated to 

 reach at least sixty miles an hour, is then more easily gauged. 



The flight track is always slightly curved, and although the 

 albatross is seen to fly more often on a level keel than the smaller 

 shearwater, both proceed by careering from side to side, rising up ten 

 or twenty feet at the end of each movement to gain height (momentum 

 is thereby lost) for the powerful downward plunge that shall carry 

 the bird skimming at speed low over the surface of the sea. The observer 

 sees first the dark back of the bird turned to him, and one wing-tip 

 all but touching the crest or side or trough of the swell, then the bird 

 rises, perhaps with one, or two, wing beats, swings slowly over, and 

 presents the (usually) white belly to view as it glides gracefully onwards 

 on the other tack. Once they have settled on a dead calm sea the 

 albatrosses and the larger shearwaters have some difficulty in rising 

 from the surface. When approached quickly in a boat, they flap 

 awkwardly for a long distance over the surface, paddling with their 

 legs, and may settle again without having got on the wing at all. If 

 they are full fed they often lighten themselves by disgorging food. 

 But in rough weather they easily launch themselves by opening their 

 wings into the wind from the top of a wave, and are airborne immedi- 

 ately. On land they need a long run to take off in fine weather if they 

 cannot drop into the air from a cliff or high rock, or unless a strong 

 wind is blowing. 



The ffight of the shorter-winged fulmars is similar, but the gliding 

 periods are shorter, and turning and banking manoeuvres are achieved 

 within a narrower compass, the wings being broader and the primaries 

 rather more flexible than those of the albatrosses and shearwaters. 



Very different is the ffight at sea of the storm-petrels and frigate- 

 petrels, which is best described as an erratic bat-like flitting, with 

 brief intervals of gliding. It has been called swallow-like, but it lacks 

 the directness of the swallow's flight, though it is almost as fast, and 

 the wings are more expanded and the whole motion more light and 

 wavering. In rough as in calm weather these little petrels follow the 

 undulations of swell and wave, keeping within a few inches of the 

 heaving surface, with an astonishing nicety. It is only when feeding 



