417 



Genus CYGNUS. 



Anser apud Brisson, Orn. vi. p. 288 (1760). 



Anas apud Linnaeus, Syst. Nat. i. p. 194 (1766). 



Cygnus, Bechstein, Gemeinn. Naturg. Deutschl. iii. p. 815 (1809). 



Olor apud Wagler, Isis, 1832, p. 1234. 



This genus is represented in the Palsearctic, Nearctic, and Neotropical Regions, the Palaearctic 

 species ranging occasionally into the northern portions of the Ethiopian and Oriental Regions, 

 and if Cygnus atratus is to be considered congeneric with our Swans, the genus is also represented 

 in the Australian Region. 



The Swans frequent both fresh and salt water, but are usually found near the shores of the 

 ocean, and not far out at sea. They swim with great ease and grace, but are clumsy and heavy 

 on shore. Their flight is strong, and tolerably swift ; and when on passage they collect together 

 in flocks. Their call-note is loud and trumpet-like, being usually uttered when they are on the 

 wing. They feed on the soft portions of aquatic plants, which they obtain chiefly from under 

 water, being able, on account of their long necks, to reach down and pluck them up ; but they 

 also eat insects, snails, worms, and frogs. 



They place their nest, which is large and bulky, on a small island, or on a tussock in a 

 morass, or in any suitable place near the water, but always on the ground, and deposit up to six 

 or seven greenish-grey or yellowish-white eggs. 



Of almost all the white Swans the young birds are grey, becoming quite white in mature 

 dress ; and in several of the species- the trachea enters the keel of the sternum, and returns 

 before proceeding to the thorax. 



Cygnus olor, the type of the genus, has the bill rather longer than the head, higher than 

 broad at the base, depressed towards the end, of nearly equal breadth throughout, rounded at 

 the end ; unguis roundish, large, convex ; edge of the bill straight, concealing the narrow blunt 

 tips of the slender low lamella? ; nostrils elliptical, median, placed near the ridge ; wings long, 

 broad, the second and third quills longest ; tail short, rounded ; legs short, stout, placed rather 

 far back ; tarsus compressed, reticulated ; hind toe small, elevated ; anterior toes longer than the 

 tarsus, the outer two about equal in length ; interdigital membranes full ; claws strong, arched, 

 rather obtuse ; plumage moderately full, close. 



141 



