Morphological and stable isotope data from sympatric cormorant species in southern Chile

This dataset contains detailed morphological measurements and stable isotope values (δ¹³C and δ¹⁵N) for two sympatric cormorant species—Imperial Shag (Leucocarbo atriceps) and Red-legged Cormorant (Poikilocarbo gaimardi)—sampled at Pirén Islet, Reloncaví Sound, southern Chile. Data were collected during both breeding and non-breeding seasons to assess individual and population-level variation in trophic niche breadth and overlap.Morphological data include mass (kg), wing length (cm), bill length (cm) and width (cm), tail length (cm), and leg length (cm) for each captured individual.Isotopic data were obtained from three tissue types (feathers, plasma, and red blood cells) to provide temporal resolution of diet and foraging ecology. Isotope measurements were performed at the University of New Mexico's Centre for Stable Isotopes using an elemental analyser coupled to an isotope ratio mass spectrometer.Methodology:Cormorants were captured at night using light-attraction techniques and hand nets.Blood and feather samples were collected following non-lethal protocols and under ethical approval (Res. N° 7850/2021, Servicio Agrícola y Ganadero, Chile; CEC-Ulagos ORD. 72/2021).All individuals were measured, banded, and released after sampling.Isotope analysis was conducted according to standard protocols, with δ¹³C and δ¹⁵N values calculated relative to international standards.Use:This dataset enables analyses of seasonal and interspecific variation in isotopic niche width, individual specialisation, and foraging strategies. It is suitable for ecological, evolutionary, and conservation research on seabird trophic ecology and coexistence mechanisms.Ethical compliance:All data collection procedures were approved by relevant institutional and government authorities, ensuring adherence to animal welfare and legal requirements.For further methodological details, refer to the associated manuscript:"Individual and population variation in isotopic niche between two sympatric cormorant species."本数据集包含智利南部雷隆卡维湾皮伦岛采集的两种同域分布鸬鹚的详细形态测量数据与稳定同位素比值（stable isotope values，δ¹³C与δ¹⁵N），涉及物种为帝鸬鹚（Imperial Shag，Leucocarbo atriceps）与红腿鸬鹚（Red-legged Cormorant，Poikilocarbo gaimardi）。 采样覆盖繁殖季与非繁殖季，旨在评估营养生态位宽度与重叠度的个体及种群水平变异。 形态学数据涵盖每只捕获个体的体重（千克，kg）、翼长（厘米，cm）、喙长与喙宽（厘米，cm）、尾长（厘米，cm）以及腿长（厘米，cm）。 同位素数据取自羽毛、血浆与红细胞三种组织类型，以反映取食生态与饮食组成的时间分辨率特征。 同位素比值测定工作在美国新墨西哥大学稳定同位素中心完成，所用设备为连接同位素比例质谱仪的元素分析仪。 采样方法： 研究人员于夜间利用光诱技术与手持网具捕获鸬鹚。血液与羽毛样本的采集遵循非致死性实验规程，并已获得伦理审批：智利农牧局Res. N° 7850/2021；智利拉各斯大学动物伦理委员会CEC-Ulagos ORD. 72/2021。所有个体在完成测量、佩戴环志后予以放生。同位素分析依照标准实验规程开展，δ¹³C与δ¹⁵N比值的计算以国际标准物质为参照。 数据集用途： 本数据集可用于分析同位素生态位宽度、个体特化现象与取食策略的季节及种间差异，适用于海鸟营养生态与共存机制相关的生态学、进化生物学及保护生物学研究。 伦理合规性： 所有数据采集流程均已获得相关机构与政府部门的审批，严格遵循动物福利相关法律法规要求。 如需进一步了解实验方法细节，请参阅关联论文：《两种同域分布鸬鹚的同位素生态位个体与种群变异》（Individual and population variation in isotopic niche between two sympatric cormorant species）。