It may seem unlikely to find Canada geese in Wales. However, since their introduction in the 17th century, they have become the most common goose species. Locally, they are called gwydd Canada. In Gaelic, their name is Gèadh-dubh. This pair was feeding along the Outer East Moat of Caerphilly Castle. Since this medieval stronghold was built in 1271, it has been the largest castle in Wales.