Urbanisation of the Eurasian Goshawk (Astur gentilis) in Finland

Abstract

Urbanisation of birds of prey is a well-known phenomenon worldwide. Common questions investigated include how does urbanisation originate and proceed and whether it is a successful or detrimental process? Here, I describe the first steps of urbanisation of the Eurasian Goshawk (Astur gentilis) in Finland, and examine how abundance and offspring production might associate to urban and non-urban goshawk populations. I predict, that if urban habitats were more favourable for goshawks than non-urban habitats, population trends should be more positive and offspring production should be higher in urban habitats than elsewhere, possibly suggesting that urbanisation was a successful process. Conversely, declining offspring production with increasing population density may suggest some detrimental process. During the study period, the urban goshawk population showed a significant increasing trend, while the number of territories recorded elsewhere in Finland decreased significantly. The average annual mean brood size was not higher in the urban population than in Finland in general. These results support to some extent the idea that the urbanisation was a successful process. However, for a longer term, the possibility that extremely high population densities in the urban environment increase intraspecific competition and lead to some detrimental consequences can not be ruled out.