SCREAMERS, DUCKS, GEESE, AND SWANS 457 



other. Not only the beak, but the skull, in certain 

 characters, recalls that of the Game-birds. The body 

 may be described as goose-like, but in the longer 

 legs and enormous toes, which are not connected by 

 a web, these birds recall the Megapodes, or Mound- 

 builders (page 411). 



The screamers are generally regarded as primitive 

 members of the group with which they are now asso- 

 ciated ; but in many respects they are quite peculiar. 

 Not the least interesting of their habits is the 

 great predilection they observe for soaring in the air 

 at immense altitudes, uttering the while the curious 

 cry to which they owe their name. Several birds 

 often do this at once. Yet stranger is the fact that 

 they not seldom gather together in vast flocks to 

 sing in concert. Mr. Hudson, for instance, states that 

 the species known as the CHESTED SCREAMER on one 

 occasion surprised him by " an awful and overpowering 

 burst of ' melody,' " which saluted him from half a 

 million of voices at an out-of-the-way spot in the 

 pampas one evening at nine o'clock; and, again, 

 once at noon he heard flock after flock take up their 

 song round the entire circuit of a certain lake, each 

 flock waiting its turn to sing, and only stopping 

 when the duty had been performed. 



Like the gannet, these birds are richly supplied 



fh,t, by J. T. Ntwman] [B.rkhamilid 



AYLESBURY DUCK 



This is one of the most esteemed of all domesticated breeds 



tli,,. bj J. 1C. 



58 



POCHARD 



This is one of the diving-ducks 



with air-cells between the body and the skin, 

 and between many of the muscles ; so highly 

 are these cells developed, that it is said a crack- 

 ling sound is emitted when pressure is applied to 

 the skin. 



The wings of these birds are armed each with 

 a pair of powerful and sharp spurs, recalling 

 those of certain of the Plover Tribe (page 421), 

 though in the latter only one spur is present on 

 each wing. 



The division of the remainder of this group 

 into Ducks, Geese, and Swans is generally recog- 

 nised, but no hard-and-fast line can yet be drawn 

 between the several sections. We must regard 

 them as representing adaptations to peculiar, 

 modes of life, which appear to be most marked, 

 in the duck-like forms. These may be divided 

 into FRESH-WATER DUCKS, SALT-WATER DUCKSJ 

 SPINY-TAILED DUCKS, and MERGANSERS. 



Of the FRESH-WATER DUCKS, the most 

 familiar is the WiLD-DUCK, or MALLARD. This 

 is a resident British bird, and also the parent 

 of the domesticated stock, which frequently 

 closely resembles the wild form. In this species; 

 as with the majority of the fresh-water ducks, 



