INSTINCT AND INTELLIGENCE IN BIRDS
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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.
