152 



NATURAL HISTORY OF BIRDS. 



while one invades the Palaearctic region, and one, our ruddy duck (Erismatura ru- 

 bida), is peculiar to North America. The birds of this family are especially charac- 

 terized by the narrow and rigid tail-feathers, which are only scantily protected with 

 coverts at the base. The strangest bird of the group is the Australian musk-duck 

 (Biziura lobata), the male of which has a large, compressed wattle underneath the 

 chin, very much like that which Sarkidiornis has on the top of the bill. It very 

 seldom takes to the wing, even when hard pressed, but it dives with great ease and 

 can remain under water for an incredible space of time. Its chief mode of progres- 

 sion is by swimming with the head and part of the neck alone above the surface. 

 The male is nearly twice as big as the female, and the color of both sexes is a blackish 

 brown. During the pairing and breeding season the male emits a strong odor of 



FIG. 73. Merganser merganser, European goosander. 



musk, which may be smelt long before the bird is seen, and hence the name. The 

 eggs, which usually are only two in number, are comparatively large, and of a pale 

 olive color ; the shell is rough and very strong. The peculiar voice of the musk-duck 

 is said to resemble " the sound caused by a large drop of water falling into a deep 

 well." 



The last sub-family consists of the mergansers, which are directly and closely 

 related to sevei-al of our sea-ducks, but adapted to a diet of living fish instead of the 

 molluscs which serve the sea-ducks for food. In consequence the bill has been greatly 

 modified. The great width, being unnecessary, has been reduced, the lamella?, no 

 longer serving as a sieve, have been changed into strong teeth which will prevent the 

 escape of the unfortunate victims, and the nail has assumed the character of a strong 

 hook. The result is that these birds are among the greatest destroyers of fish life. 



