Acta Zoologica Cracoviensia, 16() 1971
Daily flights of Rooks Corvus frugilegus Linnaeus, 1758 and Jackdaws Corvus monedula Linnaeus, 1758 winteringin Cracow
Abstract:
The behaviour of Rooks and Jackdaws w intering in Cracow was observed in two seasons, 1968/69 and 1969/70. Five flight routes were distinguished, of which the one extending over a distance of 15 km, from Mydlniki to Rybitwy, was given most attention. This route led along a valley protected by hills, raising 40-70 m. above its bottom, on the north and on the south. The degree of dependence of the flights to the feeding grounds and roosts on sunrises and sunsets was established. An attempt was made to point out the relation between the type of flight (rectilinear, undulate, forced and soaring) and the force and direction of the wind. The behaviour of birds was observed in the places of rallying, feeding and roosting. The food requirement of the whole winter population of Cracow was worked out and it is 618 x 106 kcal. which corresponds to the consumption of 772 tons of potatoes.
