THE IMPENETRABLE SEA 



facts regarding swimming birds. He mentions the gannet 

 as being one of the most efficient of all feathered divers. 

 It sometimes makes a precipitous dive into the sea from 

 a height of over one hundred feet, at an estimated speed 

 of one hundred miles an hour. The force with which the 

 bird strikes the water may be estimated from the fact 

 that a diving gannet, coming in contact with a board 

 sunk to a depth of six feet, has driven its beak so firmly 

 into the wood that its neck has been broken. 



Gannets have copious supplies of oil in their glands for 

 water proofing their feathers. Bird plumage always 

 offers some resistance to water, but the water proofing is 

 more efficient in aquatic birds. Sooty terns, which some- 

 times rest on water, become waterlogged in a few hours 

 if they remain on it, but ducks can sleep on the surface 

 for a whole night. 



Birds can control the resistance of their feathers to 

 water, probably by manipulation of the muscles at the 

 feather roots. Batten, in Inland Birds says that wild ducks 

 may swim and dive with their under-feathers quite dry, 

 but if one is shot and falls into the water the plumage is 

 immediately saturated. Dr. Bastian Schmid has told an 

 extraordinary story of some Indian runner ducks which 

 he kept: the birds had never seen a pond, having been 

 reared by a hen. Dr. Schmid sprinkled them lightly with 

 a watering-can one day, and this caused them to go 

 through all the motions of swimming and diving. 



Some diving birds have been observed to leave the 

 surface of the water flapping their wings, showing that 

 they had been using them to ''fly" to the surface, and 

 had then continued to use them, without a pause, to 

 ascend through the air. 



Closely allied to diving birds are the penguins — which 

 form the very distinct order Impennes^ and family Spheni- 

 scidae. The penguin has many resemblances to the diver 

 in the structure of its softer internal parts, and in the 

 backward position of its short legs and upright posture 



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