John Innes: National Wetlands Trust spokesperson on the plan to reintroduce rats to wetlands sanctuary to fix bird problem - Heather du Plessis-Allan Drive

A Waikato wetland sanctuary is reintroducing rats to try to stop birds pooing in a prized lake.

It's a last resort to try to scare off half a million sparrows and starlings roosting at Lake Rotopiko.

The birds defecate so much, it's changing the ecosystem and affecting the water quality.

National Wetlands Trust spokesperson, John Innes says they've released 30 rats to try and deter the birds in a first for the nation.

"This is experimental, that's the first thing, and this is all being closely monitored to see if it works. It's only one species of the twelve or thirteen mammals that were taken out and everybody's very keen that the others don't go in."

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