In most colony-breeding species, biparental care during both egg incubation and chick-rearing is inevitable for successful reproduction, requiring parents to coordinate their nest attendance and foraging time. The extent to which the rhythm of nest attendance is adjusted to temporal and spatial variation in food availability is poorly understood. Here we investigate whether the rhythm of nest attendance interacts with the spatial and temporal availability of foraging habitats in Eurasian spoonbills Platalea leucorodia breeding on Schiermonnikoog, a Dutch Wadden Sea barrier island. Spoonbills are tactile foragers that forage during both day and night in habitats of varying salinity. GPS-tracking combined with acceleration-based behavioral classification of 9 female and 13 male adult spoonbills between 2013 and 2019 revealed that, despite nearby foraging opportunities following a tidal rhythm, nest attendance followed a sex-specific diel rhythm. During incubation and chick-rearing, females attended the nest at night and foraged during the day, while males showed the reverse rhythm. Females made more and shorter foraging trips to, almost exclusively, nearby marine habitats, whereas the larger males often made long trips to forage in more distant freshwater habitats. Before and after breeding, females as well as males foraged primarily at night, suggesting that this is the preferred period of foraging of both sexes. Nevertheless, foraging habitat use remained sex-specific, being most likely explained by size-dependent foraging techniques. To conclude, the sex-specific rhythm of nest attendance is not shaped by the spatial and temporal availability of foraging habitats.

中文翻译：

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群体繁殖水鸟中性别特定的巢穴出勤节奏和觅食栖息地的利用

在大多数群体繁殖物种中，为了成功繁殖，在卵孵化和育雏期间双亲照顾是不可避免的，需要父母协调它们的巢穴和觅食时间。人们对巢穴出勤节奏在多大程度上根据食物供应的时间和空间变化进行调整的程度还知之甚少。在这里，我们研究了在荷兰瓦登海屏障岛上繁殖的欧亚琵鹭 Platalea leucorodia 的筑巢节奏是否与觅食栖息地的空间和时间可用性相互作用。琵鹭是触觉觅食者，白天和晚上都在不同盐度的栖息地觅食。 2013 年至 2019 年间，GPS 跟踪与基于加速度的行为分类相结合，对 9 只雌性和 13 只雄性成年琵鹭进行了分析，结果显示，尽管附近的觅食机会遵循潮汐节律，但筑巢行为却遵循特定性别的昼夜节律。在孵化和育雏过程中，雌性晚上出巢，白天觅食，而雄性则表现出相反的节奏。雌性几乎只到附近的海洋栖息地进行更多、更短的觅食旅行，而体型较大的雄性则经常进行长途旅行，到更远的淡水栖息地觅食。繁殖前后，雌性和雄性主要在夜间觅食，这表明这是两性觅食的首选时期。然而，觅食栖息地的使用仍然具有性别特异性，这很可能是通过大小依赖的觅食技术来解释的。总而言之，特定性别的筑巢节奏并不取决于觅食栖息地的空间和时间可用性。