Earlier studies have indicated that consumption of beavers Castor ssp. by wolves Canis lupus varies seasonally and is influenced by rainfall affecting water levels. Therefore, to determine whether these carnivores prey more often on beavers in drier seasons and years, we assessed the diet of wolves in Wigry National Park (NE Poland) by analysing 303 scats collected from 2017 to 2019. The most important prey of wolves in this region was the wild boar Sus scrofa (25.2% of consumed biomass), Eurasian beaver Castor fiber (24.4%) and roe deer Capreolus capreolus (24.2%). Predator niche breadth was broader in spring-summer (B = 2.24) than in autumn-winter (B = 1.32), mainly due to higher consumption of beavers (37.3% in spring-summer and 10.7% in autumn-winter). Wolves consumed more beavers (40.9%) and had the broadest niche breadth (B = 1.99) in 2019, when the annual rainfall was lowest. Our study provides further evidence that wolves prey on beavers more often in ice-free seasons and drier years.

早期的研究表明，海狸蓖麻的消费。狼犬狼疮随季节变化，受降雨影响水位。因此，为了确定这些食肉动物是否在较干燥的季节和年份更频繁地捕食海狸，我们通过分析 2017 年至 2019 年收集的 303 只猫来评估 Wigry 国家公园（波兰东北部）狼的饮食。区域是野猪Sus scrofa（消耗生物量的 25.2%）、欧亚海狸蓖麻纤维（24.4%）和狍狍 Capreolus capreolus(24.2%)。春夏（B = 2.24）的捕食者生态位宽度比秋冬季（B = 1.32）更广，主要是由于海狸的消费量较高（春夏为37.3%，秋冬季为10.7%）。狼在 2019 年消耗了更多的海狸 (40.9%) 并且拥有最广泛的生态位宽度 (B = 1.99)，当时年降雨量最低。我们的研究提供了进一步的证据，表明狼在无冰季节和干燥年份更常捕食海狸。