The smaller of the two, roughly 35 yards square, is ringed by a stone-faced earth-cut channel and an outer waterlogged ditch, the whole arrangement designed not for ornament but for deception. A duck decoy of this kind worked by luring wildfowl onto a central pond and then coaxing them along tapering netted tunnels called pipes, each curving away from the main water so that the birds, once in, could not easily turn back. It was a method common in the Netherlands and England but far rarer in Ireland, which makes the survival, even in ruin, of a working example in Cork quietly remarkable.

The smaller decoy dates to around 1750, when it operated with four pipes. By 1865 two of those pipes had been enlarged and the other two abandoned, suggesting the enterprise was being rationalised rather than wound down. A larger elongated pond lies roughly 100 metres to the south-east, oriented on a north-east to south-west axis, and this too served as a decoy, with arms of water at either end forming its own pipes. A new pipe was added to this second pond in 1875, indicating that decoy operations on the demesne were still being actively developed well into the Victorian period. Both ponds remained in use until the 1930s, a surprisingly long run for what was by then an archaic form of wildfowling. Since then, the water has retreated: the inner channels are dry, the outer ditches waterlogged but shallow, and the ponds themselves are overgrown and partially drained.