Researchers examined 39 years of data about a British Columbia population of Song Sparrows to identify patterns in how and why nesting success changed over time. The researchers found that factors such as rainfall, population density, and nest parasitism interacted in complex ways, with their effects waxing and waning, and that inbreeding became a significant negative factor only when it increased sharply during the middle portion of the study.

Canadian co-author: Peter Arcese, University of British Columbia –

Original paper published March 21, 2018