Lyrurus tetrax britannicus

Mathew describes it as a former resident, long extinct in spite of an attempt at re-introduction at Trecwm.  Not re-established in the county.

R.M.Lockley, G.C.S.Ingram, H.M.Salmon, 1949, The Birds of Pembrokeshire, The West Wales Field Society 

More about the Black Grouse in Pembrokeshire