Cieślińska Karolina, Manikowska-Ślepowrońska Brygida, Zbyryt Adam, Jakubas Dariusz
Department of Vertebrate Ecology and Zoology, Faculty of Biology, University of Gdańsk, ul. Wita Stwosza 59, 80-308 Gdańsk, Poland.
Doctoral School of Exact and Natural Sciences, University of Białystok, ul. Konstantego Ciołkowskiego 1K, 15-245 Białystok, Poland.
Animals (Basel). 2024 Aug 24;14(17):2461. doi: 10.3390/ani14172461.
Habitat structure on foraging ground is one of the crucial factors determining diet diversity in colonially breeding avian predators. Quantifying the habitat and diet composition at different spatial scales (regional and local inter-colonial) can help provide understanding of the drivers of diet composition. In this study, we examined the composition of the non-fish diet of an opportunistic predator, the Grey Heron (), based on pellets. We compared pellets from 21 colonies in two different regions of Poland that differing in composition of foraging habitats. Multivariate statistical techniques were used to analyze the relationship between diet and habitat compositions in a 20 km radius around these colonies. Significant inter-regional and inter-colony differences in Grey Heron diet and habitat composition were detected in foraging areas. However, some prey were present in the diet only from one of the regions. Around the heronries with a predominance of farmland habitats, the European water vole () and terrestrial invertebrates were present in relatively low frequencies, and the striped field mouse () was present in high frequencies. Voles ( sp.) were more frequent in colonies with prevalence of non-irrigated arable land around the colony, in contrast to the bank vole (), which was less common in heronries with a higher contribution of this habitat type. Remains of aquatic invertebrates were less abundant in colonies surrounded by extensive forests. The results of our research indicate the opportunistic character of the non-fish part of the diet of the Grey Heron adapted to the local foraging habitat and prey availability.
觅食地的栖息地结构是决定群居繁殖的食禽性捕食者饮食多样性的关键因素之一。量化不同空间尺度（区域和殖民地间局部尺度）的栖息地和饮食组成有助于理解饮食组成的驱动因素。在本研究中，我们基于食丸研究了机会主义捕食者苍鹭（Grey Heron）的非鱼类饮食组成。我们比较了波兰两个不同地区21个繁殖地的食丸，这两个地区的觅食栖息地组成不同。运用多元统计技术分析了这些繁殖地周围半径20公里范围内饮食与栖息地组成之间的关系。在觅食区域，检测到苍鹭饮食和栖息地组成存在显著的区域间和繁殖地间差异。然而，某些猎物仅在其中一个地区的饮食中出现。在以农田栖息地为主的鹭巢周围，欧洲水田鼠（European water vole）和陆生无脊椎动物出现的频率相对较低，而条纹田鼠（striped field mouse）出现的频率较高。与河岸田鼠（bank vole）相比，田鼠（vole sp.）在繁殖地周围非灌溉耕地占优势的繁殖地中更为常见，而河岸田鼠在这种栖息地类型占比更高的鹭巢中不太常见。在被广阔森林环绕的繁殖地中，水生无脊椎动物的残骸较少。我们的研究结果表明，苍鹭非鱼类饮食部分具有机会主义特征，适应了当地的觅食栖息地和猎物可获得性。
