500 PALMIPEDES. 



they have the power of submergino- their heads for 

 some depth below the surface of the water^ where 

 they retain them for a considerable time. Their 

 nest is formed of a heap of dry vegetable matter, 

 and the female lays from five to seven eggs. 



About the 1st of September, the Swans leave the 

 Polar Sea, and resort to the lakes and rivers in 

 and about the latitude of Hudson's Bay, where 

 they remain preparing for a departure for the 

 winter till October; when they collect in flocks of 

 from twenty to thirty, and seizing a favourable 

 opportunity, with the wind not opposed to the 

 direction of their flight, they mount high in the air, 

 form a prolonged wedge, and with loud screams 

 depart for more genial climes. When making 

 either their semi-annual transmigration, or on 

 shorter expeditions, an occasional scream, equal to 

 " How do you all come on behind V issues from the 

 leader, which is almost immediately replied to by 

 some posterior Swan, with an ^^ all's well '' vocifera- 

 tion. When the leader of the party becomes fatigued 

 with his extra duty of cutting the air, he falls into 

 the rear, and his neighbour takes his place. When 

 mounted, as they sometimes are, several thousand 

 feet above the earth, with their diminished and 

 delicate outline hardly perceptible against the clear 

 blue of heaven, this harsh sound, softened and 

 modulated by distance, and issuing from the im- 

 mense void above, assumes a supernatural character 

 of tone. — (Franlxim.) 



" In flying, these birds make a strange appear- 

 ance ; their long necks protrude, and resemble at a 

 distance long lines with black points, their heavy- 

 bodies and triangular wings seeming mere appen- 

 dages to the prolonged neck. Wlien thus in motion, 

 their wings pass through so few degrees of a circle, 

 that, unless seen horizontally, they appear almost 

 quiescent, their movements being widely difl'erent 

 from the semicircular sweep of the Goose. The 

 Swan when migrating, with a moderate wind 



