I have seen all sorts of birds 'mob' hawks and falcons.Last year I was absolutely staggered to see a group of twenty or so Swallows give chase to a Sparrowhawk to fend it away from their nest site. If someone told me that had happened I wouldn't have believed them either! But I saw it. I'd have thought a hawk would pick out a Swallow much easier than a falcon but p'raps it ain't always necessarily so - probably a juvenile Sparrowhawk in this instance, or a male, it wasn't a big 'un. I had to rack my brains to remember exactly where it was and remembered seeing a female Gos' on the drive in. I doubt the Swallows would have taken her on but that would have truly been something extraordinary to see!
There was a quote from an old Ray Mears film on some obscure telly channel the other night that stuck in my mind, 'the more time you give to Nature, the more She will reveal to you'. I'm paraphrasing but never a truer word was spoken. Very often thats the place where fishing takes us to, if we're not too preoccupied with the game in hand
I read in the 'expert' books and publications that the hawks and falcons, with the exception of the kestrel, don't take the slightest notice of this 'mobbing'.
But I'm not sufficiently expert or a dedicated enough observer to know if this is true or not.
At our model plane flying field (a large and now disused WW2 airfield surrounded by fairly 'open' forest and near-treeless patches of heathland and close to the coast and Southampton water) peregrines are common. I've noticed that they often 'play chase' peewits with no intention of catching them. Sometimes it goes on for ten minutes or so. Other hawks and falcons do it too but none are common around that field.