Proximity to anthropogenic food sources determine roosting and nesting prevalence of feral pigeons (Columba livia) in a tropical city

Abstract

The feral pigeon (Columba livia) is a globally commensal bird that can cause dis-amenities such as soiling and is a potential vector of various diseases. Aside to limiting food as a management strategy, reducing the availability of roosting and nesting sites can help regulate feral pigeon populations. Despite their prevalence, current knowledge of their roosting and nesting preferences is lacking. Feral pigeons commonly use railway viaduct expansion gaps in Singapore for roosting and nesting. These gaps provided an ideal experimental platform to examine feral pigeon roost and nest site selection while controlling for differing cavity sizes which can significantly affect their reproductive success and site selection decisions. We also conducted an in-situ experiment to test the efficacy of nest removal as a management option. Our nationwide surveys of 80.3 km of railway viaducts and 6048 gaps revealed that feral pigeon day roosting and nesting preferences are influenced by structural height and more importantly, their proximity to human food sources. There was a significantly higher probability of feral pigeon roosting in a gap if it had more pigeon feeding incidences in its vicinity and was higher. The probability of feral pigeon nesting in gap was higher if it was closer to a railway station, lower and further from water bodies. In our field experiment, we did not find any significant differences in the proportions of the abundances of feral pigeon to other urban commensal bird species at the gaps before and after nests were removed. Overall, our results suggest that a concerted effort to reduce anthropogenic food availability to feral pigeons is central in limiting their reproductive success and controlling their population.