DUCKS AND DRAKES 399 



SO far without noticing it. There is a great flock of 

 Gulls going off together — are they beginning their fall 

 journey ? " 



" No, they are only going to some harbor to feed. 

 They belong to a guild of water birds that I think we 

 might call Sea Sweepers ; for they clear from the sur- 

 face of the water the refuse that the tide would other- 

 wise throw upon the beaches. They also follow in the 

 wake of ships for the same purpose. Neither Gulls 

 nor Terns can dive far under water like Ducks, for 

 their bodies are too light ; but they all pounce down 

 on wing and contrive to catch small fish swimming just 

 below the surface. 



'' Look at the difference between the flight of the 

 two ! The Tern half folds his long pointed wings, and 

 darts down like lightning ; in a second he is up in the 

 air again dashing off with capricious flight, holding his 

 beak to his breast as the Woodcock does. But the Gull 

 sails more slowly, settles deliberately, and often floats 

 quietly on the surface ; then when he rises on wing, with 

 some ceremony, he flaps off with his beak held straight 

 before him, like a Duck. Terns are the better flyers, 

 but Gulls are decidedly the more expert swimmers." 



" Are Gulls and Terns related ? " asked Dodo. 



" They both belong to one family of many members. 

 These two that you have been watching are among the 

 best known of all — the American Herring Gull, who 

 lives on both lake and ocean ; and the Common Tern, 

 who mostly follows the sea-coast." 



'' Heads down ! " called Olaf. The boom swuno" 

 round, the sail dropped, and the boat ran into the 

 shallow Avater of the beach at Great Gull Island. 



