The Calderdale Raptor Study Group covers some, or all, of the following grid squares SD91:92:93, SE01:02:03 & SE11:12.
Effectively the southern border is the M62 with the Worth Valley in the north. In the east the Group covers Brighouse [between Bradford in the north and Huddersfield in the south]. The western border is the Pennine county boundary with Lancashire.
Information here about key species and work being undertaken.