Зоологический журнал

ONTOGENETIC CHANGES IN SPATIAL PATTERN OF BEHAVIOUR OF THE HOODED CROW (CORVUS CORNIX) ON LENIN HILLS IN MOSCOW

Grabovsky V.I.

Observations were carried out during the period from abandoning the nest to the occupation of the own territory. During the first winter of their life 89 percent of birds have their home range 2 to 3 times more spacious than their territory. Sixty-seven percent from them winter together with the parents on the parents' territories. During the nesting period a part of young birds in the first year of their life inhabit their parents' territories and 60 percent of the two years old birds concentrate their activity on small patches the areas of which are comparable with the territories; the patches are situated near the boundaries of the reproductive pair territories, far from the centres of host activity. The features of the crow population studied show the tendency to cooperative breeding; these features are as follows: high density (35 pairs per 1 km2), maintenance of off-springs — parents contacts as well as of attachment of off-springs to the birthplace for a long time (up to one year), delay of reproduction (reproduction was not registered in birds of 2 to 3 years old), formation (in the places of wintering) of relatively stable in time and structure, personalized groups with an adult pair and their off-springs of the past year as a nucleus. Non-dispersion of youngs is a mechanism of display of the tendency to cooperative breeding, and sufficiency of food, stability of food sources as well as spa­tial deficit for birds that do not nest are pissible causes of the tendency

ДВА НОВЫХ ВИДА РОДА CHRYSOTUS (DIPTERA, DOLICHOPODIDAE) ИЗ ЯКУТИИ

НЕГРОБОВ О.П., ЦУРИКОВ М.Н.