The island is not natural, or rather its purpose was not decorative. It was a trap.

A decoy pond was a wildfowling system common across Britain and Ireland from the seventeenth century onwards, in which ducks were lured by various means onto a central island or into curved, netted channels radiating outward from open water. Once the birds moved into the narrowing channels, nets closed around them. The Caltragh example appears on the 1838 edition of the Ordnance Survey six-inch map, which shows the pond clearly, with its central island and four channels running off its corners. The flow of water through those channels was regulated deliberately, presumably to control the birds' movement through the system. The site may be connected to the Eyre family, a name associated with landownership in this part of Galway, though the precise nature of any link is not firmly established. What remains on the ground today is the dried bed of the pond, the island still visible within it, and faint traces of the channel lines beneath the encroaching woodland.