Imitation or “Instinct” by a Male Thrush?

Abstract

ON the evening of July 19 a young thrush was caught in my conservatory and placed in a large outside aviary. The following morning I observed the parent birds feeding the young one through the bars with worms. In the same aviary there had been for more than ten years a male thrush which had been captured when quite young and had never been mated or troubled with family cares. On observing the parents of the young bird feeding their offspring he at once followed their example. On putting some bread and milk into the aviary he flew down, took up a piece and tried to induce the young bird to open its beak. At first the young thrush appeared to be afraid of accepting food from the foster-father, but after some persuasion it allowed itself to be fed with bread and milk, hemp seed, and other food. The parent birds were watching from the outside, and during the whole time occupied by the old male in feeding their progeny were also trying to introduce food through the bars. The day after (July 21) the parent birds did not make any further attempt to introduce food, but contented themselves by watching their young one from a tree close at hand. If any of the house-cats approached the aviary the parents would at once give the alarm. In the course of another day or two they abandoned the young one entirely to the care of the old foster-father, who has proved quite worthy of his trust, as the young bird is now able to feed himself and is in a very thriving condition. The old male still insists, however, on giving it any delicate morsel he may find. This observation appeared to me to be of sufficient interest to record in your columns, as the old male bird certainly in this case learnt how to feed the young one by observing the proceedings of the parent birds. He had never reared any young ones of his own, and had never had any opportunity of seeing other families brought up in the aviary.