Mae system gwyliadwriaeth adar gwyllt yr Asiantaeth Iechyd Anifeiliaid a Phlanhigion wedi nodi tri achos o ffliw adar ar Ynys Môn ac yng Ngheredigion, ac mae pedwar achos arall wedi cael prawf positif ar Ynys Grassholm. Mae arsylwadau pellach o adar marw neu sy'n marw wedi'u hadrodd ar Grassholm, ond amcangyfrifir bod niferoedd yn parhau i fod yn gymharol fach ac mae'n ymddangos eu bod mewn ardaloedd ynysig o'r nythfeydd.
The Animal and Plant Health Agency (APHA) wild bird surveillance system has identified three cases of HPAI on Anglesey and in Ceredigion, with a further four cases confirmed as testing positive on Grassholm Island. Further observations of dead or dying birds have been reported on Grassholm, however estimated numbers remain relatively small and appear to be in isolated areas of the colony.