CHAPTER XXIII. 

 CLASS IV. AVES (BIRDS). 



418. Laboratory and Field Studies. Each student o: 

 group of students should be encouraged to select one or more 

 species of birds and to study their habits and external struc- 

 ture in the light of the following outline. 

 I. Habits and Activities. 



Haunts and feeding habits. 



Social habits ; solitary or gregarious ? 



Mating habits; monogamous or polygamous? Degree of 

 sexual dimorphism? 



Determine and describe its powers of song. Are they 

 equally developed in all individuals of the species ? Can 

 you cite any evidence that the power is of any use to the 

 animals ? 



Nesting habits; number of eggs, their size and other char- 

 acters. Is their color of any conceivable use? Which 

 sex incubates the eggs? Condition of the young at 

 hatching and the care given by the parents to the young. 



Migrations. Are there any evidences of winter (or other 

 important) migrations? If not, how is the winter spent? 

 If so, at what time does it occur ? When does the species 

 return? Any other known facts. 



Power and peculiarities of flight. Other modes of locomo- 

 tion? Is the power of perching well developed? 



- What are its relations to the other animals of the locality? 

 Has it any enemies? Is it hostile to any species of 

 animals ? 



What is its abundance or scarcity in your locality? Can 



you assign any explanation of the facts observed? 

 II. General External Appearance. 



Regions of the body: head, neck, trunk, limbs. 



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