2io TEXT-BOOK OF ZOOLOGY 



growing plants (snails and insects), or out of the water. The legs are 

 strong, and, being articulated near the middle of the body (see ostrich), 

 enable the bird to stride about for hours without fatigue. 



3. The legs are of unusual length, the tarso-metatarsus and a portion 

 of the lower part of the tibia being naked (wading legs). These arrange- 

 ments enable the bird to wade to a considerable depth in the water, and 

 to traverse shallow ponds or pools without wetting its plumage. 



4. It also strides with ease over soft marshy soil, for the posterior toe 

 touches the ground in its entire length (compare, on the other hand, the 

 domestic fowl), whilst the surface of support is further increased by short 

 webs connecting the three broad anterior toes, and extending to their tips 

 in the form of narrow fringes. (Compare these structures with snow- 

 shoes and the sledge-like contrivances used by people engaged in shore- 

 fishing, when visiting the mud flats at low tide.) The toes being weak 

 and their claws blunt, they cannot (as in raptorial birds) be employed 

 as prehensile organs. 



5. In spite of the great height of the legs, the long neck enables the 

 bird to approach the beak, which is also of considerable length, to the 

 ground. (Why is this necessary ?) With the beak the stork picks up its 

 food, which it then, by raising its head, allows to drop down its throat. 

 It is able to kill animals of fairly large size, and to hold fast slippery 

 creatures like frogs and fishes, the beak being strong and provided with 

 sharp cutting edges. 



6. At the beginning of the cold season the animals which form the 

 food of the stork either enter upon a hibernating sleep or retire into 

 sheltering retreats. The bird is then obliged to migrate to the warmer 

 shores of Africa, where waters do not freeze and food is always abun- 

 dant. Its long wings equip it for the distant voyage, and though the 

 short tail is of little use as a rudder (compare with swallow), this deficiency 

 is compensated by the long legs, which are extended backwards during 

 flight, and serve as rudder to the feathered air-ship. 



The Black Stork resembles the common stork in all respects save 

 that the plumage, with the exception of the white under surface, is of a 

 glossy brownish-black. It nests on high forest trees, far from human 

 habitations. In Germany it is much rarer than its white relative. 



Family 2 : Herons (Ardeidae). 

 The Gray or Crested Heron (Ardea cinerea). 



(Length about 3 feet.) 



This bird in shape of body strongly resembles the stork (compare the 

 two birds) ; and though it does not despise as food any of the animals 



