Bird populations, especially on islands, have declined or gone extinct due to overhunting, habitat loss and fragmentation, and adverse effects of the introduction of non‐native species. Bahama Swallows (Tachycineta cyaneoviridis), endangered secondary cavity nesters that breed on only three islands in the northern Bahamas, are an island species with a declining population, but the causes of this decline are unknown. During four breeding seasons on Great Abaco Island (2014–2017), we identified cavity‐nesting resources used by breeding swallows in native pine forest and other habitats, and estimated phenology and breeding parameters from a subset of nests. Bahama Swallows nest in cavities in a variety of structures, but rely most on woodpecker‐excavated cavities in pine snags and utility poles. Swallows nesting in cavities in pine snags had higher fledging success (92%) than those nesting in cavities in utility poles (50–62%), which were concentrated in non‐pine habitat that may expose swallows to predation and increased competition for nest cavities from other species. The high reproductive success of Bahama Swallows nesting in the pine forest indicates that the decline in population cannot be attributed to poor productivity on southern Great Abaco. However, our results suggest that the dependence of Bahama Swallows on cavities excavated by Hairy Woodpeckers (Dryobates villosus) for nesting sites may be a factor in their decline, and highlight the potential importance of the protection and management of pine forests in future efforts to ensure the survival of Bahama Swallows.

中文翻译：

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濒危巴哈马燕子（Tachycineta cyaneoviridis）的腔体利用和繁殖生物学：对保护的意义

由于过度捕猎，栖息地丧失和破碎以及引入非本地物种的不利影响，鸟类的数量，特别是在岛屿上，已经减少或灭绝。巴哈马燕子（Tachycineta cyaneoviridis）是濒临灭绝的次生腔巢动物，仅在巴哈马北部三个岛屿上繁殖，是一种种群数量减少的岛屿物种，但这种衰退的原因尚不清楚。在大阿巴科岛的四个繁殖季节（2014-2017年）中，我们确定了在天然松树林和其他栖息地繁殖燕子所使用的窝巢资源，并从一部分巢中估算了物候和繁殖参数。巴哈马燕子在各种结构的洞中筑巢，但大多数情况下都依赖于啄木鸟在松树杆和电线杆中挖出的洞。燕子在松枝窝中筑巢的成功率（92％）比电线杆在巢中筑巢的成功率（50-62％）要高，后者集中在非松树栖息地中，这可能会使燕子遭受捕食并增加对巢穴的竞争来自其他物种。巴哈马燕子在松树林中筑巢的繁殖成功率很高，这表明人口减少不能归因于大阿巴科南部的生产力低下。但是，我们的结果表明，巴哈马燕子对长毛啄木鸟（筑巢点的枯萎病可能是其下降的一个因素，并突出了保护和管理松树林在未来确保巴哈马燕子生存中的潜在重要性。