VERTEBRATES 143 



3. Define and give illustrations of the meaning of the 

 expressions : " land birds ; " " water birds ; " " shore birds ; " 

 " swamp birds ; " " scavengers ; " " policemen of the air." 



4. Discuss the temperature of birds, the amount of en- 

 ergy they show, and the oxygen they use. 



5. Beaks of birds. 



6. Feet of birds. 



7. The crop and gizzard. Why absent in many birds .' 



8. What is there in a bird's construction which enables 

 it to twist its head so far around ? What are the advan- 

 tages in being able to do so .' 



9. Account for the oiliness of plumage of water birds ; 

 for the complete feathering of legs and feet in some forms. 



10. Define moulting and discuss its advantages and dis 

 advantages.. 



11. Give reasons why you would not expect a bird to 

 hibernate. 



12. Name two or more kinds of birds which show 

 "recognition marks." What sort of birds would you ex- 

 pect to find with such marks ? Why .' 



13. Is a bird's egg alive when it is laid.' Why does it 

 have so much food stored in it .' What direct interest have 

 we in this fact ? 



14. How are the eggs of various birds protected while 

 they are developing .-' 



JVote. — Do not be satisfied with only one way. A bird seldom is. 



15. Compare praecocial and altricial birds as to their 

 stage of development when hatched ; the location and 

 character of the nest ; the care given by the parents ; the 

 singing habit of the parents ; the success of the type. 



16. Name at least three insect-eating birds and tell how 

 many insects it is estimated each will destroy in a day. 

 Effect in a garden .■• 



