Best places for bird watching in Pembrokeshire?

I'm going to Pembrokeshire next week for five nights and have most of the stay planned, but on one afternoon my mum is going to go round Pembroke Castle whilst my dad and I do something else (castles aren't our thing and she'd rather go round on her own anyway). Does anyone have any recommendations for good bird watching locations to spend the afternoon at that aren't too far away from Pembroke? Say, within half an hour or so at most. It would be nice to see choughs, but any suggestions will do!