Breeding success of the Eurasian eagle owl (Bubo bubo) and rodent population dynamics

Abstract

The dependence of the breeding success of the eagle owl on the population dynamics of rodents, which are a staple of its diet in Mordovia, was traced. At peak numbers of rodents, large clutches and a high survival rate of fledglings were observed in the breeding pairs; after a year of depression of rodent populations, in the following year, the pairs do not nest at all or their breeding success is reduced to a minimum due to the death of the clutches. In 52% of the cases, the nesting pairs laid three eggs; in 31%, two eggs; in 9%, four eggs; in 4%, one egg or five eggs. The average clutch size was 2.78 ± 0.17. The average number of chicks grown from a successful nest was 2.41 ± 0.27. The nests in Mordovia were located at a distance of 1.1–3.7 km from residential areas.