ZOOL.— Vol. II.] LOOMIS— CALIFORNIA WATER BIRDS. 353 



journeys have apparently rendered familiar. With the 

 young educated into a knowledge of the way, heredity, as 

 a factor in migration, is stripped of its potency — at most 

 there remaining only an innate desire for travel and an 

 "inherited talent for geography."^ Under the guise of 

 science the word heredity may harbor as great superstition 

 as the word hibernation in an earlier period in the study of 

 migration. Outward necessity exists for the early move- 

 ments — coming winter with its failure of food. Whether 

 old birds comprehend that they must depart early in order 

 that the exodus migration may be a gradual depopulation 

 is hidden from us. Supplementary migration, owing to 

 sudden contraction in the food area, seems to indicate an 

 intelligent appreciation of the necessity of migration. 

 Whatever be the case, young birds might readily acquire 

 the habit of migration by following the example of old trav- 

 elers, who in youth had acquired the habit in like manner 

 from their elders. " In its early days the developing animal 

 is reading the paragraph of life. Every sentence mastered 

 is built into the tissue of experience, and leaves its impress 

 on the plastic, yet retentive brain. By dint of repetition, the 

 results of acquisition become more and more firmly in- 

 grained. Habits are generated; and habit becomes second 

 nature. The organism which to begin with was a creature 

 of congenital impulse and reaction becomes more and more 

 a creature of acquired habits. It is a new being, but one 

 with needs not less imperious than those with which it was 

 congenitally endowed."^ 



In short, it is held that birds-of-the-year, inheriting prob- 

 ably a desire for travel and a talent for geography, learn 

 early exodus migration from the old birds, and that habit 

 (possibly also foresight) holds the old birds to route and 

 period of movement, thus maintaining the adjustment to 

 winter with its failure of food. 



1 Cf. Calif. W. B. No. IV, p. 315. 



2 C. Lloyd Morgan on 'Instinct and Intelligence in Animals,' 'Nature,' Vol. I,VII, 

 8, p. 329. 



