Data from: A comparative study of insect abundance and reproductive success of barn swallows Hirundo rustica in two urban habitats

Few studies have quantified the relative reproductive success of passerines in urban habitats. I studied food availability and reproductive success of barn swallows Hirundo rustica in two urban habitats during 2012–2015. Barn swallows breeding in the town center experienced lower insect densities than those in the town periphery. Lower food availability resulted in reduced feeding rates per capita, lower nestling body mass, longer nestling periods, longer inter-clutch intervals, fewer first and second brood fledglings and a lower total number of fledglings produced during the breeding season in comparison to barn swallows breeding in the town periphery. I hypothesize that the lower intra-specific competition for nest sites and fitness advantages linked to the solitary breeding in urban habitats balanced the apparent costs of reproduction in more urbanized habitats.

目前鲜有研究量化雀形目鸟类（Passerines）在城市生境中的相对繁殖成功率。2012至2015年间，我针对两类城市生境中的家燕（Hirundo rustica）的食物可获得性与繁殖成功率展开了研究。相较于城镇近郊的家燕种群，城镇中心繁殖的家燕所面临的昆虫猎物密度更低。食物可获得性的匮乏会导致一系列负面影响：个体日均投喂频次降低、雏鸟体重偏低、雏鸟育雏期延长、窝间间隔变长、首窝与第二窝的出飞幼鸟数量减少，且整个繁殖季的总出飞幼鸟数量相较于城镇近郊繁殖的家燕种群显著降低。据此我提出假说：城市生境中巢址种内竞争的降低，以及独居繁殖所带来的适合度优势，能够抵消更高城市化程度生境中繁殖的显性成本。