Wetlands Revival Trust, a conservation-minded group of farmers, build a wildlife haven in a swamp

Now in their eighties, Ken and Jill recently decided it was time to part with their wetland. (ABC Landline: Tim Lee)

For ecologist Damien Cook there's no sweeter sound than the near-deafening dawn and dusk chorus of birds and frogs at Wirra-Lo wetland.

Among them is the distinctive gravelly croak of the nationally endangered growling grass frog, re-discovered here in 2017, and the mating call of the equally rare Australasian bittern, once a common bird on the inland flood plains.