Tree cavities are an essential requirement for reproduction and survival of secondary cavity nesters. Little is known, however, about how cavity distribution in space and time may limit their use during and outside of the breeding season. Using long-term (17 yr) data on the use of nest-boxes resembling tree cavities by individually marked Eurasian pygmy owls Glaucidium passerinum, we compared the habitat and the distances among the nest-boxes used during two different seasons. We found that pygmy owls are more demanding in their requirements for breeding than for food-hoarding habitat, as the habitat surrounding the nesting sites had a higher proportion and biomass of coniferous forests, especially spruce, and nesting sites were farther from houses than food-hoarding sites. Pygmy owls mainly used different nest-boxes for nesting and food-hoarding and they also used different nest-boxes in different years. The distance between the nest site and food-hoarding sites was longer when the main food availability (voles) was low than when it was high. The distance was also longer in females than in males, probably indicating that females need to move further to find suitable hunting areas. In conclusion, these results highlight the importance of spruce forests as a nesting habitat of pygmy owls, and the need of several tree cavities within their home range. Forest management should secure a sufficient supply of these resources at the scale of pygmy owl home ranges.

树洞是次生巢穴繁殖和生存的基本要求。然而，人们几乎不了解在繁殖季节内外的时空分布会如何限制它们的使用。使用长期（17年）的数据，通过单独标记的欧亚侏儒猫头鹰格氏青ci使用类似于树洞的巢箱，我们比较了两个不同季节使用的栖息地和巢箱之间的距离。我们发现侏儒猫头鹰对繁殖的要求比对食物栖息地的要求更高，这是因为筑巢地点周围的栖息地所占比例较高，针叶林的生物量（尤其是云杉）以及筑巢地点离房屋远比食用食物远。 ard积场所。矮小猫头鹰主要使用不同的巢箱进行嵌套和食物储藏，并且在不同年份也使用不同的巢箱。当主要食物的可利用量（数量）较低时，筑巢地点与食物储存地点之间的距离要比较高时大。雌性的距离也比雄性的距离长，这可能表明雌性需要进一步移动才能找到合适的狩猎区。结论，这些结果凸显了云杉林作为侏儒猫头鹰筑巢栖息地的重要性，以及在其家园范围内需要几个树洞的需要。森林管理应确保在侏儒猫头鹰的家园范围内提供足够的这些资源。