I went to Llyn Bodgyllched near Beaumaris a few weeks ago to see the Starling roost which seemed a bit low and I thought it was due to low immigrant numbers this winter. But I didn't realise they were all at Llanfaelog! Wait for the next calm clear evening and head for the Llanfaelog turn-off for Rhosneigr/Oyster catcher restaurant (Abeffraw end of the A55 - Rhosneigr/Aberffraw road). Especially if there is a nice sunset it should be awesome!
Please park sensibly, take care and enjoy!