Groot verschil in ontwikkeling tussen jonge Wespendieven Pernis apivorus in hetzelfde nest

On 5 August 2000, two nestling Honey Buzzards were ringed, weighed and measured in the eastern Netherlands. The eldest weighed 880 grams and its age was estimated at 41 days old (maximum wing chord 325 mm); the youngest weighed 740 grams and had a wing length of 202 mm (equivalent to 24 days old). Both were in excellent condition and had a full crop; the nest also contained a large number of empty wasp combs. It is unlikely that this huge difference reflected a similar discrepancy in laying date. Several other suggestions are given.