Abstract Urban forests are important hotspots of biodiversity in the environment of cities and their surroundings but may also stand out from neighbouring forests by greater tree species diversity, higher tree age and greater share of deciduous species. However, they are usually not connected with nesting of rare birds of prey, especially dietary specialists. Unexpectedly, I have found Honey Buzzard Pernis apivorus nesting in such a forest in a 300,000-inhabitant city in North-Eastern Poland. The male of this pair was caught and fitted with a global positioning system logger. Using a tree cover density raster, I show that both for nesting and foraging, Honey Buzzards preferred dense canopies. Even with anthropogenic disturbance, the urban forest still offered the best conditions (greatest tree cover) for this specialist species in a 10 km radius. This finding shows that the advantages of some features of urban forests (deciduous character, dense canopy) can overcome disadvantages of the urban environment even for rare, large raptors. Also tree cover density seems a promising indicator of biodiversity in urban forests and should be tested in larger studies.

中文翻译：

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树木覆盖密度吸引稀有猛禽专家在城市森林中筑巢

摘要 城市森林是城市及其周边环境中生物多样性的重要热点，但也可以通过更大的树种多样性、更高的树龄和更大的落叶物种份额而在邻近森林中脱颖而出。然而，它们通常与珍稀猛禽的筑巢无关，尤其是饮食专家。出乎意料的是，我在波兰东北部一个拥有 300,000 名居民的城市的这样一片森林中发现了蜂蜜秃鹰 Pernis apivorus 筑巢。这对雄性被捕获并安装了全球定位系统记录器。使用树木覆盖密度栅格，我表明无论是筑巢还是觅食，Honey Buzzards 都喜欢密集的树冠。即使有人为干扰，城市森林仍然为 10 公里半径内的这种特殊物种提供了最佳条件（最大的树木覆盖率）。这一发现表明，即使对于稀有的大型猛禽，城市森林的某些特征（落叶性、茂密的树冠）的优势也可以克服城市环境的劣势。此外，树木覆盖密度似乎是城市森林生物多样性的一个有希望的指标，应该在更大规模的研究中进行测试。