During an intensive study of the urban population of the Blackbird Turdus merula in Szczecin (1997-2023), four cases of surrogate copulation were observed in the Blackbird and three in the Fieldfare Turdus pilaris. In three cases birds (Blackbirds twice and Fieldfare once) try to copulate with fledglings of their own species, in all other cases the birds try to copulate with moss and sticks. In three cases copulation attempts were done by adult birds (two blackbirds and one fieldfare), in four cases it was a fledgling.

Inter-specific adoption is an intriguing topic in behavioural and evolutionary ecology. Being a rare phenomenon is rarely documented in the literature and thus reports of inter-specific adoption based on solid data are particularly valuable. Here, owing to a long-term and extensive monitoring of a local population of the European blackbird (Turdus merula, hereafter blackbird), we describe observations of alloparental behaviour exhibited by blackbirds towards fieldfare (Turdus pilaris) nestlings (single nest, first record ever) and fledglings (twelve cases in total). We discuss the observations in respect to available literature.