Breeding biology of House Crows (Corvus splendens) in Durban,South Africa

Nesting House Crows Corvus splendens were studied in the suburb of Merewent, Durban, South Africa, during the summer breeding season of 1999–2000. The c. 1km² study area supported 52–62 pairs. Breeding dispersal was clumped, suggesting a level of colonial breeding, but pairs were apparently intolerant of conspecifics nesting in the same tree. The two closest simultaneously active nests were 30m apart in adjacent trees. Details of nest locations, trees, heights, structure, dimensions and weights are provided. Egg-laying occurred October–January, mainly mid October to end November. Clutch size, egg dimensions and weights are given. Apparent repeat clutches were found but there was no evidence of double brooding. Details of nestling growth, and fledging and post-fledging dependence periods, are provided. Breeding success was relatively poor. Early breeding attempts were more successful than late breeding attempts. Breeding failure was suspected, or known, to be associated with observer disturbance, egg breakage, failure of eggs to hatch, starvation of chicks, nest collapse and independent control measures.