A paper in Animal Behaviour was published, reporting the results of a large-scale analysis of breeding-site fidelity in cliff swallows. We used data on over 45,000 individuals re-caught in successive years to study factors causing birds to return to their previous year's site or disperse elsewhere. Fidelity to the past year's site is affected by multiple variables, but the principal conclusion was that birds were more likely to return to last year's colony site if the colony there was similar in size to the previous year's, and if the site had been fumigated to remove swallow bugs.
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