THE WADING AND SWIMMING BIRDS. 179 
sometimes called Blue-stocking, from the color of its legs, 
The Stilt Plovers, remarkable for the great length of 
their legs, are included among the Avocets. 
290. The Rail family are characterized by their long 
toes, enabling them to walk easily over soft mud or even 
the leaves of water-plants. Some of the tribe have for 
this purpose membranous margins along the sides of the 
toes, so that the foot 
may have a consider- 
able flat surface. The 
acanas, of which a 
specimen is given in 
Fig. 146, can walk on 
the broad leaves of 
water-plants, and, as 
these leaves sink a lit- 
tle as the foot press- 
es on them, the bird 
has the appearance 
of walking on the wa- 
ter. These birds are 
found in Asia, Africa, 
and America. The 
ee specimen represent- 
so aun eer ed in the figure is the 
species found in Brazil and Guiana. 
291. Birds of the order Natatores have a peculiar pro- 
vision for swimming. They are web-footed; that is, the 
toes are connected together by a membrane or web, as 
seen in Fig. 147 (p. 180), so that the feet can be used as 
oars or paddles. In the act of swimming, the toes are 
brought near together when the foot is carried forward, 
and they are spread out when it is carried backward. 
The body of the bird is boat-shaped, so as to move 
through the water easily. In those which are the most 
aquatic in their habits, the feet are placed far back, so 
that they may propel the body effectively ; and this gives 
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