Birds are able sometimes to discriminate between protectors and persecutors, but seldom very well I should imagine; they do not view the face only, but the whole form, and our frequent change of dress must make it difficult for them to distinguish the individuals they know and trust from strangers. Even a dog is occasionally at fault when his master, last seen in black and grey suit, reappears in straw hat and flannels.
Nevertheless, if birds once come to know those who habitually protect them and form a trustful habit, this will not be abandoned on account of a little rough treatment on occasions. A lady at Worthing told me of her blackbirds breeding in her garden that they refused to be kept from the strawberries when she netted the ripening fruit. One or more of the birds would always manage to get under the net; and when she would capture the robber and carry him, screaming, struggling and pecking at her fingers, to the end of the garden and release him, he would immediately follow her back to the bed and set himself to get at the fruit again.

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