As avian reproductive success is generally prey limited, identifying important prey types or sizes and understanding mechanisms governing prey availability are important objectives for avian conservation ecology. Irruptive White Ibis (Eudocimus albus) nesting at coastal colonies in the southern Everglades numbered over 100,000 nests in the 1930s. A century of drainage and altered hydrologic patterns reduced aquatic prey availability and eliminated large nesting events; nesting activity in recent decades has been typically less than 5% of historical peaks. Hydrologic restoration is expected to increase ibis nesting activity, but which prey types will support high nesting effort is less clear. In 2017 and 2018, we collected food boluses from White Ibis chicks at coastal colonies in Everglades National Park. We also monitored regional nesting activity from 1999 to 2018. In 2017, the region had 1,075 nests, typical of the past several decades; but in 2018, there were 30,420 nests, representing the highest recorded nesting activity in 87 yr. Prey composition varied between years; estuarine crabs dominated nestling boluses in 2017, while crayfish and fish were dominant prey in 2018. Crayfish, especially Procambarus alleni, were heavily exploited by ibis early in the 2018 breeding season, while fish were used more at the end. Crayfish abundances in wetlands near the colonies were higher prior to 2018, and more crayfish-producing short-hydroperiod wetlands remained available for ibis foraging in 2018. Our results support previous studies indicating that crayfish are important prey for breeding ibises and suggest that unprecedented, extensive flooding of seasonal wetlands promoted crayfish production and initiated the irruptive breeding in 2018. Our observations indicate that rehydration of the southern Everglades could restore ibis nesting activity at coastal colonies, but further investigations of hydrologic variation, crayfish production, and ibis foraging and nesting activity will be helpful to understand these dynamics and the importance of short-hydroperiod wetlands.

中文翻译：

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干扰性的白宜必思繁殖与沿海大沼泽地淡水小龙虾的使用有关

由于鸟类繁殖成功通常受限于猎物，因此识别重要的猎物类型或大小并了解控制猎物可用性的机制是鸟类保护生态学的重要目标。1930 年代，在大沼泽地南部沿海殖民地筑巢的侵入性白宜必思 (Eudocimus albus) 数量超过 100,000 个。一个世纪的排水系统和改变的水文模式减少了水生猎物的可用性并消除了大型筑巢事件；近几十年的筑巢活动通常不到历史峰值的 5%。预计水文恢复将增加宜必思筑巢活动，但哪些猎物类型将支持高筑巢努力尚不清楚。2017 年和 2018 年，我们在大沼泽地国家公园的沿海殖民地收集了白宜必思雏鸡的食物丸。我们还监测了 1999 年至 2018 年的区域筑巢活动。2017 年，该地区有 1,075 个巢穴，是过去几十年的典型；但在 2018 年，有 30,420 个巢穴，是 87 年来有记录的最高筑巢活动。猎物组成因年份而异；河口螃蟹在 2017 年以雏鸟为主，而小龙虾和鱼类是 2018 年的主要猎物。小龙虾，尤其是 Procambarus alleni，在 2018 年繁殖季节初期被宜必思大量捕捞，而鱼类则在后期使用更多。2018 年之前，栖息地附近湿地的小龙虾丰度较高，2018 年仍有更多的小龙虾生产短水期湿地可供朱鹭觅食。我们的研究结果支持先前的研究，表明小龙虾是朱鹮繁殖的重要猎物，并表明前所未有，