BIRDS, THEIR STRUCTURE AND ADAPTATIONS 289 



separtae web like the coot, or a web connecting all four, like the 

 pelican, or only the front three, like the ducks and geese. 



The birds of prey (hawks, owls, and eagles) have the toes provided 

 with powerful claws and muscles which constitute their " talons" 

 for catching food. While at the other extreme are birds like the 

 swifts, hummers, and whip-poor-wills, which have very tiny and 

 weak feet, since they live on insects or nectar, and spend most of 

 their time in the air. 



Birds which wade along the shores in search of food have long, 

 slender legs, like the heron, snipe, crane, and plover, while in diving 

 birds, such as the loon and duck, the legs are so short and so far 

 back as to make walking very awkward. 



Beaks. Just as great a range of adaptation is shown by the 

 beak of the bird. In all cases it is light, strong, and horny, thus 

 avoiding weight. With each class of birds the beaks vary, depending 

 on the nature of their food and the manner of catching it. 



The hook-shaped, strong beak of the hawk and owl is a familiar 

 adaptation for the birds of prey while the very sharp, chisel-shaped 

 beak of the woodpecker enables him to drill deep into the trees 

 for nest holes and for food. Birds like the swifts, nighthawks, and 

 whip-poor-wills, which catch insects on the wing, have weak but 

 enormously wide beaks, often surrounded by hairlike feathers, 

 making a regular trap to catch their food. The duck's wide beak 

 with toothed edges is provided for scooping food from the mud 

 and straining it out between the notches when the head is shaken, 

 while the slender and sensitive beak of the snipe is used to probe 

 in the mud for single pieces of food. Parrots use their short-hooked 

 beak for defense, food-getting, and for climbing. Sparrows and 

 finches have short straight beaks for crushing seeds. The crossbill 

 has developed a real pair of pliers for opening cones, which contain 

 the seeds he eats, while at the other extreme is the humming bird 

 with its delicate tubular beak, able only to suck the nectar of 

 flowers. 



Nervous System and Sense Organs. To properly coordinate 

 and control so complicated and highly adapted an organism, a 

 well-developed brain is necessary. In birds, for the first time, the 





