DEATH-TRAPS FOR PIRATES 25 



with great effort. This is particularly the case 

 with the Albatrosses, which have sacrificed muscular 

 power to gliding capacity, and elongated and nar- 

 rowed their wings, to a very risky extent. 



On the Australian coast there is a valley ending 

 in a cliff-wall which is a regular death-trap for the 

 local Albatrosses which pass over it on their way 

 home to a breeding-ground. If, when coasting 

 over this hollow, they dip between the walls, they 

 lose the wind, begin to drop, and not having suffi- 

 cient strength of wing-beat to "get up steam " in 

 the limited space in front of them, end by colliding 

 with the cliff at the end of the gully, when they 

 fall to the ground to die a lingering death from 

 hunger, for the walls of the valley are too steep 

 for them to climb, and they have not enough 

 intelligence and enterprise to explore a cave at 

 the cliff-foot which would lead them out into the 

 open again. 



Another example of the dangers of over- develop- 

 ment of wings is to be found in the appropriate 

 fate of hanging that now and then befalls the piratical 

 Frigate-bird in the West Indies, as described by 

 Dr. P. Lowe ; this species, like so many tropical 

 waterfowl, frequents trees, but may easily miss its 

 footing when alighting and slip down among the 

 twigs, where its great wings cannot have full 

 play, and it is exceedingly likely to catch its neck 

 in a fork, when its very much reduced feet are of 

 little use in its attempts to extricate itself, and 

 it soon perishes. 



