How can one....?

• After posting an extended entry below, explaining how one can.... (tell the difference between moths and butterflies, not to mention grasshoppers and crickets), alongside Swift Half and general (county) updates, I thought I'd start a "How can one...." series of posts as I am often asked these questions out in the field.
• I've recently moved offices -now I have a view through a large window (with some new colleagues and office neighbours) and already pointed out sparrowhawks, kestrels and peregrines to them - and yes they'd like to know how I can tell the difference from pretty poor views.
• I'll start this series of posts with raptors around this neck of the woods - very often if I'm with a few people and I see a raptor high in the sky, I'll identify it and am then asked how can I be sure?
• Here's how, then, to tell the difference between common raptors round here, without a decent view.
• Round here, but replicated in many parts of the UK, if I see a raptor in the sky, regularly it'll be a sparrowhawk, kestrel, buzzard or kite. Sometimes it'll be a hobby or a peregrine also.
• I can't be completely sure of size, or plumage markings, so I have to rely on behaviour - what its doing and more importantly, how its doing it!
• In brief then...
• Red kites - often more than one in the sky - unlike other raptors which are more often than not (when not breeding) alone in the sky. Play with the wind - a tail twitch here, a wing flick there, but not much else. Tend to hang their wings or hold them flat. Often quite vocal (more so than buzzards) because they flock more than the similarly-sized buzzards.
• Buzzards - wings invariably held in a very shallow V shape - kites don't tend to do this. Spotted perching far more often than kites. In Scotland the buzzard is known as the telegraph pole eagle, for obvious reasons! Less vocal than kites, less often found in flocks.
• Sparrowhawk - apart from the fact that you'll often know when you're about to see a sparrowhawk by the very distinctive alarm call of starlings in particular, if you see a hawk in the sky, it'll invariably be holding its wings very flat and punctuating glides with a series of short, rapid wing beats. This is pretty-well a hawk giveaway a lot of the time. If you see a bird of prey that goes "flap flap flap flap gllllliiiide. Flapflapflapflap gliiiiiiiide" - you can be quite confident that its a hawk.
• Kestrel - the windhover is really the only common raptor that hovers in one spot in the sky for any period of time, looking down, and flapping its wings quickly. There are other raptors that will attempt that occasionally, some with a little success- but the kestrel is really the only true hoverer. Tends not to use thermals or soar like kites, buzzards and hawks.
• I'll not go into the harriers (which tend to quarter low over scrubs or reeds), goshawks (which are really just supersized sparrowhawks), hobbies (dainty little falcons which rush around bringing down dragonflies etc...) or peregrines (large, solid falcons, which fly with that in mind) - but that covers the four most common raptors round 'ere - kites, kestrels,buzzards and sparrowhawks. Thats how I tell the difference without relying on physical appearance or size  you don't need to get a good close up or lengthy view- never a good idea to rely on that. Rely on where the thing you've seen is (often habitat) and behaviour instead!