Have a look in the current (Autumn) issue of Birdwatching Magazine and I have a feature on raptor identification, the emphasis being on the criteria which should be considered when sorting out raptors in the field.The take-home message is, that by using this approach plumage detail becomes of far less importance than wing-to-tail ratios, habitat, behaviour and flight pattern.Given the number of distant sightings of silhouetted birds we get compared with close-ups this enables much more confident identification - even at great distance.