Unusual breeding of the Grey Heron (Ardea cinerea) and Crested Tit (Lophophanes cristatus) in urban environment

Urbanization changes natural environments by transforming the landscape and reducing local biodiversity. However, some urban areas with heterogenous habitats can represent a supplementary breeding environment for non-urban birds. Successful and unusual breeding of Grey Heron (Ardea cinerea) and Crested Tit (Lophophanes cristatus) was found in Zvolen city (C Slovakia). Three pairs of Grey Heron bred successfully in trees in the green fragment of abandoned riparian vegetation in the old bed of Slatina river, nearby Zvolen castle in city center in 2020 and 2021. The mean start of breeding was delayed by three weeks in comparison to known data from former Czechoslovakia. Furthermore, breeding of the Crested Tit was documented in the cavity of a panel house insulation. Five chicks fledged on May 10, a little bit earlier than the known fledging period in Central Europe. Position of nests, breeding success and phenology is described and discussed for both species.