By ANNE BESTON
The distinct "bonking" sound made by male banjo frogs during the mating season is being used to track the illegally introduced pest.
Ministry of Agriculture and Forestry staff, along with Auckland Regional Council scientists, have set up recording equipment at Huia in the Waitakere Ranges which imitates the frog's
distinctive mating call. The calls sound like a banjo string being plucked.
The equipment will then record for nine seconds to see if any answering calls are made by banjo frogs in the vicinity.
Despite months of searching, the scientists have had no luck tracking the frogs since tadpoles and froglets were found at Huia last year.
Banjo frogs are native to Australia and were probably illegally introduced here. They are aggressive predators that pose a threat to native species, including the endangered native Hochstetter frog.
They are toad-like with a rough and warty body and range in colour from pale grey to dark brown or black. The frog's glands secrete poison which deters other predators.
They are nocturnal and burrow under the ground during the day. They are often dug up by gardeners in their homeland.
"We are hoping not to hear any," said regional council resource scientist Brenda Greene.
She said native frogs did not make any sounds, so any sounds captured on the tape would come from introduced species.
