Multiple brooding in Barn Swallows (Hirundo rustica): Extrinsic determinants and implications on population growth

Abstract

In many species of birds, the number of broods produced in a breeding season is an extremely important component of reproductive success. However, for many multi-brooded species, we have a poor understanding of both the specific factors that affect the incidence of the behaviour and the impact that changes in the incidence have on population growth rates. Without this information, conservation strategies aimed at protecting multi-brooded species at risk may miss targets for conservation interventions. Therefore, I assessed the implications of multiple brooding on the conservation of a species at risk, the Barn Swallow (Hirundo rustica), in New Brunswick and Nova Scotia, Canada. To do this, I first identified extrinsic factors that affect the behaviour to inform potential intervention. Then, I assessed the influence of multiple brooding on the population growth rate to inform the extent to which changes in multiple brooding would impact the status of the population.