This is the chubbiest little Robin that I have seen; in fact, many of the ones I encounter seem somewhat slender. Looking into this, it seems to be somewhat of a mystery as to why robins get chubby like this. It typically happens in early spring; some think it's so that they have more protection from the cold during the winter months. Others think that they need to be more weighty for the activities of mating and nest building, which are energy intensive.
