School of Geography, University of Nottingham, Nottingham, United Kingdom.
Department of Conservation Ecology and Entomology, University of Stellenbosch, Matieland, South Africa.
PLoS One. 2024 Jul 15;19(7):e0304740. doi: 10.1371/journal.pone.0304740. eCollection 2024.
Dietary studies are essential to better understand raptor ecology and resource requirements through time and space, informing species habitat use, interspecific interactions and demographic rates. Methods used to collect data on raptor diets can constrain how dietary analyses can be interpreted. Traditional approaches to study raptor diets, such as analysis of pellets or prey remains, often provide dietary data at the local population level and tend to be restricted to pairs during the breeding season. The increasing use of citizen science data has the potential to provide dietary inferences at larger spatial, demographic and temporal scales. Using web-sourced photography, we explore continental-scale demographic and latitudinal dietary patterns between adult and non-adult Crested Caracaras (Caracara plancus), throughout the species' range across the Americas. We analysed 1,555 photographs of caracaras feeding and found no age effects on the probabilities of different food groups being included in photographs. The probability of reptiles being included in photographs of caracaras from the northern population was significantly higher than those from the southern population, with the opposite pattern for birds. There were significant latitudinal effects with the probabilities of fishes and invertebrates in the diet of northern caracaras increasing towards the equator. Contrastingly, the probability of mammals in the diet increased away from the equator for both populations. Assuming the focal species is well-sampled, web-sourced photography can improve our understanding of raptor diets at large-scales and complements more traditional approaches. This approach is more accessible to raptor researchers without access to the field or expertise in physical prey identification techniques.
饮食研究对于更好地了解猛禽的生态和资源需求至关重要，包括随时间和空间的变化、物种生境利用、种间相互作用和种群增长率等方面。用于收集猛禽饮食数据的方法会限制对饮食分析的解释。传统的猛禽饮食研究方法，如粪便或猎物残留物分析，通常只能提供局部种群水平的饮食数据，而且往往局限于繁殖季节的成对猛禽。公民科学数据的日益普及有可能在更大的空间、人口和时间尺度上提供饮食推断。本研究使用网络来源的照片，探索了成年和未成年的凤头卡拉鹰（Caracara plancus）在美洲各地的物种范围内的大陆尺度和纬度的饮食模式。我们分析了 1555 张凤头卡拉鹰进食的照片，发现照片中不同食物组的出现概率与年龄无关。来自北部种群的凤头卡拉鹰照片中出现爬行动物的概率明显高于南部种群，而鸟类则相反。饮食中鱼类和无脊椎动物的出现概率存在显著的纬度效应，北部凤头卡拉鹰的饮食中鱼类和无脊椎动物的概率随着向赤道的增加而增加。相反，两种种群的哺乳动物在饮食中的概率都随着离赤道的距离增加而增加。假设研究的焦点物种被充分采样，那么网络来源的照片可以帮助我们更好地了解大型猛禽的饮食，并且可以补充更传统的方法。这种方法对于没有野外经验或实体猎物识别技术专业知识的猛禽研究人员来说更容易获得。
