Den's Ring ouzels were still in the quarries late afternoon (Ring ouzels high on cliffs here SN 07958 30140, view from here SN 07920 30166). They were mostly feeding on the cascading cotoneaster berries high up on the quarry sides. Be very careful in the quarry and keep well away from the edge of the flooded quarry, there are sheer drops and slippery edges and plenty of trip hazards - thats the risk assessment sorted!
According to the Milford Haven Port website there's a tanker from Texas out in the Haven at the moment, if the grackle has a return ticket now's its chance to get home.