INSTINCT AND INTELLIGENCE IN BIRDS 141 
tribes than this, where, on one expedient proving unsuccessful, after a 
sufficient trial had been made of it, another was immediately resorted 
to.” 
A similar habit has been attributed to the gull, but with how much 
truth I am unable to say; the exact history of its origin, in either case, 
would be of much interest. -It would seem to have arisen either from 
accident or from ideas, for the question of imitation can here be ruled 
out, so far as the initial performance in a given individual is con- 
cerned. The very rarity of the habit, attested by the fact that it has 
been so seldom reported, seems to clearly point to an accidental origin, 
and to the conclusion that it does not rise above the level of associative 
memory. 
