Pictorial work of Antonello da Messina during the Sicilian period (1455-60) is considered less fruitful and less mature than during his stay in Venice (c. 1474-1476). While some art critics consider the painting “Saint Jerome in the study” a work of the first period, others believe that it was carried out during the Venice period. The Authors analysed the plumage characters of the Rock Partridge (Alectoris graeca) depicted with symbolic significance in the painting, to try the identification of the population which the subject used as model could belong to. However, they conclude that identification as Sicilian as well as Alpine Rock Partridge is doubtful and in this case the plumage of the bird depicted does not help to resolve the controversy of painting dating.