These aren't very good photos, but the Sparrowhawk doesn't always pose for its photo like some birds. This one was being mobbed by the swallows over the visitor centre (hence the odd pose). The female is all over brown, with bright yellow eyes. The male is more blue/grey in colour with a pale pink streaked front. His eyes are a deeper yellow. From this view it's difficult to tell. Goshawks (very similar, but larger) can also be seen at Cragside, but most sightings will be sparrowhawks.