...Werner Müller; Giannino Patone ABSTRACT The flight feathers and their coverts of a European kestrel Falco tinnunculus have been tested for their air transmissivity. The transmissivity was measured in both directions, i.e. from ventral to dorsal and vice versa ; the mean difference between the two...

...John Videler; Alex Groenewold ABSTRACT Hunting kestrels were observed to hang, almost without wing-flapping, in fixed positions over a sea dike. The height and position with respect to the dike profile, the wind direction and velocity and the percentage of hunting time without wing beating were...

...J. J. Videler; G. Vossebelt; M. Gnodde; A. Groenewegen ABSTRACT Two kestrels, a male and a female, were trained to fly over 50 and 125 m in a windless corridor. Both distances were flown with or without dead weights attached to the feet during 13 flight sessions for each bird. Added weight...

...J. J. Videler; A. Groenewegen; M. Gnodde; G. Vossebelt ABSTRACT A male and a female kestrel were trained to fly over a mirror in a corridor, with lead weights attached to the feet to increase weight in the range 0–0·6 N (0–61 g). Films taken at 200 frames s −1 allowed three-dimensional analysis...

...G. R. Spedding ABSTRACT The wake of a kestrel gliding down a 36 m long corridor was examined using multiple-flash stereo photographs of small bubbles of helium in soap solution. Qualitatively and quantitatively, the wake is very similar to that which would be measured behind an elliptically loaded...

...G. R. Spedding ABSTRACT The structure of the wake behind a kestrel in medium-speed flight down a 36 m length of corridor was analysed qualitatively and quantitatively by stereophoto grammetry of multiple flash photographs of the motion of small soap-covered helium bubbles. The wake consists...

...J. J. Videler; D. Weihs; S. Daan ABSTRACT The hunting flight of the kestrel (Falco tinnunculus) consists of short bouts of flight at wind speed against the wind with the eyes in a fixed position relative to the ground, and of short flights from one such position to the next. High speed films taken...