Artificial nests for Barn Swallows Hirundo rustica: a conservation option for a declining passerine?

Abstract

ABSTRACTCapsule: Barn swallows Hirundo rustica using artificial nest cups had greater reproductive success than those building and using natural nests.Aims: To quantify reproductive success of Barn Swallows breeding in artificial man-made nests and compare with those using natural nests.Methods: In 2012–16, the breeding attempts of 231 pairs of Barn Swallows were monitored in artificial and natural nests in an urban habitat in Denmark.Results: Pairs breeding in old natural nests and artificial nests bred earlier, laid more eggs, and produced more nestlings and fledglings than pairs breeding in new natural nests. Inter-clutch intervals were shorter in Barn Swallow pairs using artificial nests and old natural nests. Nest cup volume and nest volume of newly built nests were significantly larger and more variable than artificial nests excluding an effect of nest size as an explanation for the larger clutches laid in artificial nests. Increased energy and time costs of nest construction may have reduced reproductive success for pairs building natural nests.Conclusion: Artificial nests were readily accepted by Barn Swallows, they had a similar low predation rate as natural nests, and they proved to be a possible conservation option for this declining passerine breeding in urban habitats as evidenced by their 75% higher reproductive success in artificial nests.