Abstract:
The rock (Corvus frugilegus frugilegus L.) is one of 103 species grouped into 26 genera of the family Corvidae (Blake and Vaurie, 1962). Corvids are adaptable, almost cosmopolitan and may represent the most "advanced" stage of avian evolution; much of their behaviour suggests a highly developed intelligence and some species such as the rook have a complex social organisation (Thomson, 1964). The rook is gregarious in all its activities, and nests in lasting colonies in groups of tree called rookeries. It has an omnivorous diet.
C.f. frugilegus breeds from Ireland in the west to the sources of the Yenissei River, Russia, in the east; from the Persian Gulf in the south to the White Sea in the north, (Malmberg, 1971). It is replaced by two smaller allied forms, Corvus frugilegus tschusii in north Persia, Turkestan and south-west Siberia and by Corvus frugilegus pastinator in china, Japan and east Siberia (Witherby et al., 1952).
