School of Biological Sciences/Te Kura Mātauranga Koiora, The University of Auckland/Te Whare Wānanga o Tāmaki Makaurau, Auckland, New Zealand.
National Institute of Water and Atmospheric Research Ltd, Wellington, New Zealand.
J Anim Ecol. 2021 Jul;90(7):1776-1786. doi: 10.1111/1365-2656.13496. Epub 2021 May 14.
Urbanisation and anthropogenic alteration of ecosystems has led to conflict between humans and wildlife. Such conflict is often observed in apex predators. Although human-wildlife conflict has been extensively studied, male/female differences in behaviour are rarely considered. We investigated male/female differences in foraging behaviour of the predatory/scavenging brown skua Catharacta antarctica lonnbergi breeding on a New Zealand island nature reserve in proximity to farmland. These skuas are subject to culling, when perceived as a threat to livestock. As part of a long-term ecological study, we used high-resolution Global Positioning System (GPS) devices to characterise the space-use of foraging brown skuas. We also analysed stable isotopes of carbon (δ C) and nitrogen (δ N) from modern and archived blood samples to investigate possible changes in diet over the past ~30 years. Analysis of 100 GPS tracks collected from 2014 to 2016 demonstrated that males and females consistently visited different habitats. Males spent most of their time close to their breeding territory on the island nature reserve and females frequently visited a farmed island approximately two kilometres away. Consistent with this finding, we show that male and female skuas also differed markedly in their diets: males specialised on burrow-nesting white-faced storm petrels Pelagodroma marina (80%) with only a small proportion of sheep remains Ovis aries (<6%) contributing to their diet. In contrast, female diet comprised 27% white-faced storm petrels, other seabirds (18%) and a relatively large proportion of sheep remains (47%). Further, our data (186 blood samples from 122 individuals) show that this male/female difference in diet has persisted at least since 1987. Because females fed disproportionally on sheep remains, they may be more vulnerable to being culled by farmers. Importantly, our case study suggests that intersexual differences in diet and foraging patterns can have major implications for the reproduction and survival of apex predators that interact with farming. We strongly suggest that intersexual differences in behaviour should be considered when investigating human-wildlife conflicts.
城市化和生态系统的人为改变导致了人类与野生动物之间的冲突。这种冲突在顶级捕食者中经常观察到。尽管人类与野生动物的冲突已经得到广泛研究，但很少考虑行为上的雌雄差异。我们调查了在新西兰一个靠近农田的岛屿自然保护区繁殖的捕食/食腐棕海鸥 Catharacta antarctica lonnbergi 的雌雄觅食行为差异。这些海鸥被认为对牲畜构成威胁时会被扑杀。作为一项长期生态研究的一部分，我们使用高分辨率全球定位系统 (GPS) 设备来描述觅食棕海鸥的空间利用情况。我们还分析了来自现代和存档血液样本的碳 (δ C) 和氮 (δ N) 的稳定同位素，以研究过去约 30 年来饮食可能发生的变化。从 2014 年到 2016 年收集的 100 个 GPS 轨迹分析表明，雄性和雌性始终访问不同的栖息地。雄性大部分时间都在岛屿自然保护区的繁殖领地附近度过，而雌性则经常访问大约两公里外的一个养殖岛屿。与这一发现一致的是，我们还表明，雄性和雌性海鸥的饮食也有明显差异：雄性专门以洞穴筑巢的白脸海燕 Pelagodroma marina 为食（80%），只有一小部分绵羊遗骸 Ovis aries（<6%）构成其饮食的一部分。相比之下，雌性的饮食包括 27%的白脸海燕、其他海鸟（18%）和相对较大比例的绵羊遗骸（47%）。此外，我们的数据（来自 122 个个体的 186 个血液样本）表明，这种饮食上的雌雄差异至少从 1987 年就已经存在。由于雌性不成比例地以绵羊遗骸为食，它们可能更容易受到农民的扑杀。重要的是，我们的案例研究表明，与农业相互作用的顶级捕食者的饮食和觅食模式的性别差异可能对其繁殖和生存产生重大影响。我们强烈建议在调查人类与野生动物的冲突时，应考虑行为上的雌雄差异。
