Behavior and diet data collected from i) GPS video camera collars and ii) fecal samples collected from individuals from the Fortymile Caribou Herd

Summer diets are crucial for large herbivores in the subarctic and are affected by weather, harassment from insects and a variety of environmental changes linked to climate. Yet understanding foraging behavior and diet of large herbivores is challenging in the subarctic because of their remote ranges. We used GPS video-camera collars to observe behaviors and summer diets of the migratory Fortymile Caribou Herd (Rangifer tarandus granti) across Alaska, USA and the Yukon, Canada. First, we characterized caribou behavior. Second, we tested if videos could be used to quantify changes in the probability of eating events. Third, we estimated summer diets at the finest taxonomic resolution possible through videos. Finally, we compared summer diet estimates from video collars to microhistological analysis of fecal pellets. We classified 18,134 videos from 30 female caribou over two summers (2018 – 2019). Caribou behaviors included eating (mean = 43.5%), ruminating (25.6%), travelling (14.0%), stationary awake (11.3%) and napping (5.1%). Eating was restricted by insect harassment. We classified forage(s) consumed in 5,549 videos where diet composition (monthly) highlighted a strong tradeoff between lichens and shrubs; shrubs dominated diets in June and July when lichen use declined. We identified 63 species, 70 genus and 33 family groups of summer forages from videos. After adjusting for digestibility, monthly estimates of diet composition were strongly correlated at the scale of the forage functional type (i.e., forage groups comprised of forbs, graminoids, mosses, shrubs, and lichens; r = 0.79, p < 0.01). Using video collars, we identified i) a pronounced tradeoff in summer foraging between lichens and shrubs and ii) the costs of insect harassment on eating. Understanding caribou foraging ecology is needed to plan for their long-term conservation across the circumpolar north and video collars can provide a powerful approach across remote regions.

Methods
This dataset was collected from GPS video-camera collars worn by female caribou of the Fortymile Caribou Herd spanning Alaska, USA and Yukon, Canada.

夏季日粮对于亚北极区域的大型植食动物至关重要，其受天气状况、昆虫侵扰以及诸多与气候相关的环境变化影响。然而，由于亚北极区域大型植食动物的活动范围极为偏远，对其觅食行为与夏季日粮组成的研究颇具挑战。本研究依托GPS视频项圈（GPS video-camera collars），对分布于美国阿拉斯加州与加拿大育空地区的迁徙性四十英里驯鹿群（Fortymile Caribou Herd, Rangifer tarandus granti）的行为模式与夏季日粮开展观测。研究首先对驯鹿的行为类型进行了表征；其次验证了利用视频量化进食事件发生概率的可行性；再者通过视频以尽可能精细的分类学分辨率估算了夏季日粮组成；最后将视频项圈得到的夏季日粮估算结果与粪便颗粒显微组织分析法（microhistological analysis of fecal pellets）的结果进行了对比。

2018至2019年两个夏季期间，研究团队共对30头雌性驯鹿采集得到18134段视频。驯鹿的行为类型包括进食（占比均值43.5%）、反刍（25.6%）、移动（14.0%）、静息清醒（11.3%）与小憩（5.1%）。进食行为会受到昆虫侵扰的限制。研究对5549段记录到进食行为的视频进行了饲用植物分类，月度日粮组成分析结果显示，地衣与灌木间存在显著的权衡关系：6月与7月间灌木在日粮中占主导，而地衣的利用占比则有所下降。通过视频分析，本研究共鉴定出夏季饲用植物的63个物种、70个属与33个科。在校正消化率（digestibility）后，日粮组成的月度估算结果在觅食功能群（forage functional type，即由草本、禾草类、苔藓、灌木与地衣组成的饲用类群）尺度上呈现出极强的相关性（r=0.79，p<0.01）。

借助GPS视频项圈，本研究明确了两点核心发现：其一，夏季觅食过程中地衣与灌木间存在显著的资源权衡关系；其二，昆虫侵扰会对进食行为产生显著成本代价。环北极北部地区的驯鹿长期保护规划需要依托对其觅食生态学的深入理解，而视频项圈技术可为偏远区域的相关研究提供强有力的技术手段。

## 数据集采集方法
本数据集采集自分布于美国阿拉斯加州与加拿大育空地区范围内的四十英里驯鹿群雌性个体所佩戴的GPS视频项圈。