160 NEW YORK ZOOLOGICAL SOCIETY. 



they have been accorded the value only of a subfamily, Cygniiicc, 

 in the great Order Anseres. 



To-day only seven species of swans inhabit the earth,* and of 

 the tens of thousands of swans which must have lived and died in 

 the past, fragmentary bones of but four or five have been discov- 

 ered embedded in the rocks of the Pliocene and Pleistocene peri- 

 ods. These fossils have been found in caves in Belgium and in 

 Malta, and remains have also been discovered in Oregon and in 

 New Zealand. The Falconer Swan of Malta was a giant among 

 swans, being said to exceed by one-third any of the living species. 

 South America seems to have been well suited to the maintenance 

 of generalized types of birds, such as the seriema and screamer ; 

 and in this matter of swan relationship we find some help in a 

 bird from that continent called the coscoroba duck, goose, or 

 swan, as we prefer. Although perhaps closer to the geese, yet this 

 bird possesses a number of interesting swan-like characteristics, 

 which place it in an intermediate position. It feeds on land, how- 

 ever, has its lores feathered, the tips of its primaries black, and 

 frequently utters a loud, rather musical call — something like 

 ■chuck-cha-caw ! 



Although swans are so preeminently aquatic in their habits, 

 yet one of the birds closely related to them on the side of the 

 geese is the semipalmated goose of Australia, perhaps the most 

 terrestrial of all its family, and which in consequence has all 

 but lost the webs between its toes. So much for the relationship 

 of the swans. 



The seven living species of swans are most conveniently treated 

 in three groups : First, the Black Swan of Australia ; second, the 

 Black-Necked Swan of southern South America; and third, the 

 remaining five species of pure white birds — the Whooping, Be- 

 wick, Whistling, Trumpeter, and Mute Swans — inhabiting the 

 arctic regions of both hemispheres. It is interesting to note that 

 none of the species inhabits the tropics. The Black Swan is ac- 

 corded a genus of its ow^i — CJieiiopsis; but the other six are all 

 grouped together as Cygniis. 



With our present slight knowledge it is idle to speculate upon 

 the origin and former distribution of the swans, especially of the 

 southern species. The contiguous boreal distribution of the five 

 arctic birds, with occasional crossing into each other's territory, 

 accounts for the slight differences existing between the three spe- 

 cies of the Eastern and the two of the Western Hemispheres. 



* The collection of swans in the New York Zoological Park is now 

 complete, all seven species being on exhibition. 



