Nest site selection of the house crow (Corvus splendens), an urban invasive bird species in Singapore and implications for its management

The house crow (Corvus splendens) has reached pest proportions in Singapore and requires an integrated system of population control measures. One such crucial component, possibly reducing its breeding success, was the focus of our study. We compared the nest sites (n=30) of the house crow with randomly selected sites (n=30) to determine which environmental variables, if any, are indicative of preferred nest sites. The chi-squared test revealed the yellow flame tree (Peltophorum pterocarpum) to be the preferred tree species used for nesting. We formulated our model based on 11 preselected variables using binary logistic regression and evaluated the strength of support for each model (relative to all other models) using the second order model selection criterion AICc. The results indicate that house crows selected nests in areas that were more urbanised and open, with higher disturbance, nearer bin centres and food centres, and nested in trees that had larger crown volume, density and diameter. Based on these results, we suggest that urban managers can alter the landscape characteristics to make them less conducive for nesting crows. Such measures might include minor adjustments to the design of existing bin centres to prevent crows from entering, planting alternative, less suitable tree species in future, and regular pruning of trees with larger and denser crowns.