I am blessed to live in Oxfordshire, when it comes to Red Kites. They are plentiful and quite reliable if you set out to photograph them. The biggest challenge is to find a spot of blue sky for your background, as a typical English white featureless sky will 'bleed' into the head and neck feathers resulting in a wash-out.
Right now [April] the Kites are flying around our skies in pairs and the occasional trio [usually a second male, hoping to move in on the female after a squabble]. Today in Abingdon, there were two groups of Kites. Each group consisted of three pairs. Amazing to watch them using the thermals to glide around the countryside.
Below are some images of my local raptors.