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? Meution the eight factors govern- 
ing tne character of birds’ nests and give examples illus- 
trating each. 
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 precocial birds larger than those of altri- 
cial birds? Give examples. What are the extremes in © 
the period of incubation ? Do both sexes incubate ? 
The Young (Chapter VI, page 70).—The mental and 
physical growth of the Chicken form 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 instinctively recognize water, etc., and at the 
same time notes should be kept of its changes in plumage. 
