THE PIGEON 197 



How does the food of birds reach the blood ? How does 

 the blood reach and become part of the tissue? How does 

 the tissue waste away and get out of the body? 



What is the process of locomotion in birds? Is it any 

 harder for a bird to fly than it is for an insect? Why? 

 Can a bird move in the air without flapping its wings ? Are 

 any of the birds awkward flyers? Is there any connection 

 between the keel and the flight of the bird? Why? 



Make a list of the birds that migrate. At what time 

 of the year do they migrate ? Why do they not all migrate ? 

 Make a list of the singing birds and of the birds that do 

 not sing. 



Are birds friends or enemies of insects? In what way 

 do they affect insects, and at what stages of development? 



Are birds injurious or helpful to man? Should they be 

 protected by law? 



Make a list of birds that are helpful to man, and also 

 a list of those that are injurious. 



Investigate the following birds; find where each belongs 

 in the classification given, and also whether useful or in- 

 jurious to man: 



Owls. Bluebird. 



Kingbird. Swallow. 



Jay. Warbler. 



Crow. Lark. 



Robin. Woodpecker. 



Oriole. Thrush. 



Phoebe. Pigeon. 



Cuckoo. Goose (Wild). 



Blackbird. Vireo. 



Bobolink. Martin. 



English Sparrow. Woodpecker. 



Hawk. Quail. 



