Buizerd Buteo buteo met zeven handpennen in de linkervleugel

A 2nd calender-year female Common Buzzard was captured and ringed on 28 February 2001, weighing 875 g. She was recaptured on 4 January 2003, some 2 km away from the initial capture site near Almere in Flevoland (body mass 913 g). It turned out that the three outermost primaries in the left wing were completely gone. Closer inspection revealed that this part of the wing had been damaged and healed, apparently having resulted in permanently damaged follicles, of which no trace was found, and tissue damage. The moult pattern differed substantially between both wings, especially in the primaries. Whereas 9 out of 10 primaries of the undamaged right hand had been renewed, only 2 out of 7 remaining primaries in the left wing were new. It is hypothesized that this discrepancy might have resulted from a departure from the normal moult cycle in order to optimize its flight capacity under duress, caused by damage in the left wing. The bird was resighted on 25 January, apparently in good health and flying without difficulties.