Common kestrel (Falco tinnunculus, Falconiformes, Falconidae) in colonial settlements of rook (Corvus frugilegus, Passeriformes, Corvidae) in steppe ecosystems of the Manych valley

Abstract

Relationships between the state of common kestrel (Falco tinnunculus) population and the structure of rook (Corvus frugilegus) colonies located in the steppe ecosystems of the Manych valley (Rostov region, Russia) were studied. A brief description of the biology and ecology of the satellite species is given. A relation between the egg-laying date and patterns of common kestrel and the structure of the rook colony was revealed: the larger the area of the rookery and the density of nesting rooks in it, the more compressed is the formation timing of its clutches. The breeding success of common kestrel was found to be the highest for the slot on side branches (71.1%) and at a height of 6.0–7.0 m above the ground (83.0%). It was shown that the a small falcon females nesting in the biological center of the rook colonies to have a smaller span of ages and more synchronous breeding compared with the females nesting on the periphery. The species forming a mixed colony have different spatial and ethological structures. The biological center of the common kestrel colony is located on the periphery (both geometric and biological) of the rook colony, and the biological edge of the colony is in the center of the rookery.