I T has always been a disputed point as to whether the Rook (Oorvus f. frugihgus) gets its bare " face " by means of abrasion of the feathers or by a moult. Most ornithologists have favoured the moult theory or have regarded it as a " natural peculiarity." This conclusion has been reached, however, by inference rather than by actual experiment. A few somewhat trivial experiments have been made with ca...

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