BIRDS CONQUEST OF THE AIR 



735 



Chap. 36 



pery fish is helpless. The pelican scoops fishes into its great pouch as into an 

 aquarium, lets the water strain away, then tosses the fish in the air to come 

 down headfirst into its gullet. Other meat eaters, the hawks, eagles, and owls 

 seize small animals with their feet and tear the flesh with the hooked end of 

 the upper mandible. Bills may be insect traps, hedged at the base with stiff 

 hairs as in the phoebe and other flycatchers, widely opened as well as hedged 

 in the night-flying whippoorwills. Delicacy of sensation is remarkable in the 

 bills of birds that search muddy pond bottoms with their bills or that probe for 

 worms in moist earth. The upper mandible of the woodcock is extremely sensi- 

 tive and so flexible that it can be moved without opening the angle of the jaw. 

 With its bill driven deep into the soil it feels about and seizes the worm. In 

 the meantime, its eyes set well back in the head have a clear lookout for 

 danger, though they are of little use in hunting wrigglers on the ground. The 

 seed-eating birds, sparrows, goldfinches, cardinals, grosbeaks, pigeons, and 

 domestic fowls, usually have simple pointed bills, that are strong at the base. 

 Crossbills pick the seeds from pine cones with special nutpicks, their crossed 

 mandibles. 



The tongue is also a food-collecting tool. That of a sapsucker ends in a 

 brush but in the insect-eating woodpeckers it bears spines and teeth. The 

 tubular tongue of hummingbirds ends in two brushes suited for nectar dip- 

 ping. In fish-eating birds such as pelicans, the tongue is very small and well 

 out of the way of the fishes slipping down the throat. 



Relatively few birds are pure vegetarians. As fledglings almost all are fed 

 on bits of animals or animal products. Both young and adults of many species 

 live upon a miscellany of small animals in summer and revert to buds and 



-~>^v 



General use 

 Pigeon 



Seed and nut cracker 

 Parrot 



^v*,. 



General use 

 Blue Joy 



.fl^^r^'^-<~^_ 



v^'" 



Shucking seeds from pine cones 

 Crossbill 



Seed and berry picker 

 Grouse Quail 



Fig. 36.6. Beaks of birds that live on mixed or on purely plant diet. (Not drawn 



to scale.) 



