SUBJECTIVE LESSONS. 79 



male differs from the female, what seasonal chang-e in 

 color may occur ? If the sexes are alike, is there nmch 

 variation in color ? 



The Molt (Chapter III, paj^es 37, 38).— ITow are chanf^os 

 in a bird's plumafre chiefly accomplished i Is the process 

 of moltinj^ subject to much variation ? What are these 

 variations apparently dependent on ? At what time of the 

 year do all birds molt ? What usually occurs the follow- 

 ing spring- ? Do any birds have a complete spring molt ? 

 Are special plumes ever acquired at this season ? Describe 

 the manner in which the Snowflake gains its breeding 

 dress. 



Color and Food (Chapter III, page 39). — How is the 

 color of Canaries sometimes altered ? What is the effect 

 of red pepper on fowls ? What is sometimes fed to Par- 

 rots to change their color ? How do Flamingoes and Scar- 

 let Ibises illustrate the relation between color and food ? 

 What color does the Purple Finch become in captivity ? 



Color and Climate (Chapter III, pages 39-41). — How 

 does climate affect the colors of birds ? What does this 

 demonstrate ? How many races of Song Sparrows are 

 known ? What relation exists between their colors and 

 tlie climate of the regions in which they live ? Where are 

 the extremes in color found ? Are these extremes con- 

 nected ? What is the prevailing character of the colore 

 of Arizona birds ? Of northwest coast birds ? What are 

 these races of birds ? Under what conditions might they 

 become species ? 



Color and Haunt and Habit (Chapter III, pages 41-44). — 

 What is necessary to an understanding of the value of 

 the colors of birds ? What is the office of protective color- 

 ing ? What of deceptive coloring ? What are the prevail- 

 ing colors of ground-inhabiting birds ? Give examples. 

 Are tree-inhabiting birds brighter than those that live on 

 the ground ? What explanation is advanced to account 

 for this ? How do we receive an erroneous idea of the col- 

 ors of tropical birds ? Wliat has Mr. Thayer proved ? 

 What fact does he call attention to ? How does this tend 

 to conceal the animal ? How does Mr. Thayer demon- 

 19 



