Bardsey is the only sizeable Welsh offshore island in North Wales locates off the Lleyn Peninsula. Bardsey is also the most beautiful and diverse, surprisingly so, because it appears little more than a large rocky lump from the mainland.  In reality, four-fifths of its 180 hectares are cultivated and low-lying, unsuspected richness hidden from mainland eyes by 548 foot high Mynydd Enlli.

Bardsey Bird and Field Observatory was founded in 1953. A group of keen birders and naturalists from the West Midlands visited the island and saw that Bardsey would be an excellent site not only for studying birds, but also for studying the whole complex ecology of a small island.

The Observatory was formed by a group comprising representatives of the Birmingham and West Midland Bird Club, the West Wales Field Society, inhabitants of the island, and interested people from Caernarfonshire. Subsequently the Bardsey Island Trust was formed when the island came up for sale in the mid-seventies

Members of the Observatory and some of the locals from Gwynedd initiated the purchase of the island and formed the Trust, whose main aim is to conserve the rich heritage and natural history of the island.

Bardsey Bird Observatory is the only fully accredited observatory in Wales and is one of a growing network of around 20 bird observatories in the British Isles. It is a registered charity.