The brood size in the Finnish Northern Goshawks seems to be associated with the breeding habitat and the availability of suitable prey. In this study, we examined these relationships in three study areas of different landscape structure in southern Finland, including a recently colonized urban area. The most abundant prey categories found in the food remains of the goshawk included corvids, turdids, columbids, gallinaceous birds, and squirrels. Corvids dominated in the diet samples of all the study areas. The number of turdids and columbids in the samples was significantly higher in both the rural and the urban habitats than in the wilderness area. The number of gallinaceous birds was significantly higher in the wilderness area than in other habitats. Gallinaceous birds, particularly tetraonids, the traditional staple food of the Northern Goshawk in Finland, seemed to be largely compensated by corvids in the wilderness area and by corvids and columbids in the rural and urban areas. The amount of corvids in prey showed a positive relationship with brood size, suggesting some particular importance of this prey in the goshawk diet. In all, diet seemed to explain partly between-landscape variations in the brood size of the goshawk. The brood size was significantly higher in the urban landscape than elsewhere.

中文翻译：

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芬兰南部农村和城市北部苍鹰的饮食和育雏大小 Accipiter gentilis

芬兰北方苍鹰的幼鸟大小似乎与繁殖栖息地和合适猎物的可用性有关。在这项研究中，我们在芬兰南部不同景观结构的三个研究区域（包括一个最近被殖民的城市地区）检查了这些关系。在苍鹰的食物残骸中发现的最丰富的猎物类别包括鸦科动物、泥鳅、鸬鹚、鸡类鸟类和松鼠。Corvids 在所有研究区域的饮食样本中占主导地位。在农村和城市生境中，样本中的粪便和菌斑数量均显着高于荒野地区。野生地区的鸡类鸟类数量明显高于其他栖息地。鸡类鸟类，特别是四子类，芬兰北部苍鹰的传统主食，似乎在很大程度上被荒野地区的鸦科动物以及农村和城市地区的鸦科动物和鸬鹚所补偿。猎物中鸦科的数量与幼鸟大小呈正相关，表明这种猎物在苍鹰饮食中具有特殊的重要性。总而言之，饮食似乎可以部分解释苍鹰育雏大小的景观差异。城市景观中的育雏大小明显高于其他地方。饮食似乎可以部分解释苍鹰幼鸟大小的景观差异。城市景观中的育雏大小明显高于其他地方。饮食似乎可以部分解释苍鹰幼鸟大小的景观差异。城市景观中的育雏大小明显高于其他地方。