HOW SOME GROWN-UP BIRDS GET A LIVING. 139 
nules, which are more aquatic, have swimming mem- 
branes on their feet, and while vegetable feeders to 
some extent they dive for food; and beyond are the 
grebes—divers almost strictly with legs set far back 
for it, but rather shallow water haunters. Beyond 
still are the loons—often called divers—which haunt 
deeper waters and live on fish only, being able to fly 
under water, and actually pursue and capture the fish. 
Further waterward still are the auks, with very short 
wings and habits that keep them always at sea and 
rarely in the air except when migrating. Further on 
this aquatic trend finds at the south pole its extreme 
in the penguins, whose wings have lost their feathery 
form and appear as fins, and flight under water is all 
that is left to them since flight in the air was aban- 
doned. They are almost helpless afoot on land. 
More landward from the grebe-loon region starts 
the geese, ducks and swans. Some (sea) ducks dive 
exclusively for fish, and have teethlike notches in the 
edges of their beaks; other ducks and the geese haunt 
the edges of the water where it is shallow, and have 
strainers on the margins of their flat scooping bills to 
let the water through and yet retain the small animal 
creatures. Many eat vegetable green parts and seeds 
also, and some geese graze almost exclusively and have 
long legs—a sort of storkward or waderward hint. 
The swan develops the long neck for reaching from 
the surface, and the flamingo has both long legs and 
neck and retains a strainer beak, but, unlike the goose 
forms, the beak is bent down, and he uses it upside 
down, as if standing on his head. He has the fringes, 
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