Twee jonge Wespendieven Pernis apivorus, een boommarter en een gevleugelde predator

A nest of a Honey Buzzard in northern Belgium (Groot Schietveld, Antwerpen province) was situated at a height of 5.75 m in a birch on open heathland (in use as military training ground), some distance away from the nearest (coniferous) forest. On 18 July 2023 the two chicks differed considerably in development, the oldest weighing 630 g (maximum wing chord 230 mm), the youngest 365 g (wing 108 mm). In the morning of 21 July, four prey transfers were recorded. On 22 July a Pine Marten was observed climbing the nesting tree and using the nest for resting and grooming. The adult female unsuccessfully tried to dispatch the marten. The nest was found to be empty, but the initial conclusion that the Pine Marten must have been responsible for the nest’s demise was later questioned. It is equally possible that the nest had been depredated earlier that day (or the previous day) by some other predator (e.g. Goshawk, of which begging fledglings were heard nearby).