Reproduction management affects breeding ecology and reproduction costs in feral urban Pigeons (Columba livia)

Abstract

Reproduction management of natural popsulations can have long-term consequences that have to be examined to avoid unwanted side effects. Management policies of urban Pigeons ( Columba livia Gmelin, 1789) include the set up of public Pigeon houses that aim at limiting hatching rate by egg removal. However, long-term consequences of this management method on the ecology of this species are still unknown. In this study we examined how egg removal affected egg-laying cycles of Pigeons by using a powerful method of time-series analysis, the wavelet method. We compared egg-laying cycles in Pigeon houses exposed to different management treatments and found that egg-laying cycles were shorter (4 weeks) in Pigeon houses with egg removal compared with control Pigeon houses without egg removal (11 weeks), suggesting that Pigeons respond to egg-removal pressure by multiplying reproduction attempts. Furthermore, we found that egg quality, an important index of female condition, was negatively affected by egg removal. This result suggests that the observed increase of egg production can lead to an increase of reproductive physiological costs and to a decrease of female condition. This study raises issues about potential consequences of such a management procedure on parasite resistance and health status of urban bird populations.