82 SUBJECTIVE LESSONS. 



as nest-builders been classified ? Do both sexes assist in 

 nest-building ? How much time may be consumed in the 

 construction of a nest ? Mention the eight factors govern- 

 ing the character of birds' nests and give examples illus- 

 trating each. (See Plates XXVI, XXVIII, XXIX, XCII 

 toC.) 



The Eggs (Chapter VI, pages 68-70).— How many eggs 

 may compose a full set ? If the nest is robbed, will the 

 eggs be replaced ? Give illustrations. Of what is the egg- 

 shell composed ? To what is the color of eggs due ? How 

 may variations in color be effected ? Is there much varia- 

 tion in the color of the eggs of the same species ? Why 

 are the eggs of prsecocial birds larger than those of altri- 

 cial birds ? Give examples. What are the exti'emes in 

 the period of incubation ? Do both sexes incubate ? (See 

 Plates XCI to C.) 



The Young (Chapter VI, page 70).— The mental and 

 physical growth of the Chicken forms an excellent and 

 practical lesson in the development of a young bird. A 

 newly hatched chick may be procured and placed in a 

 suitable cage in the class-room, where its actions and 

 plumage may be closely studied. Experiments may be 

 made, showing how little inherited knowledge the chick 

 possesses, by giving it bits of worsted, etc., to eat, and ob- 

 serving how it learns what is and what is not edible, how 

 it does not instinctiveh^ recognize water, etc., and at the 

 same time notes should be kept of its changes in plumage. 



