"Since the late 1940s there have only been three others found, one of them in Hawke's Bay and the other near Ohakune," Mr Hoare said. "It's a very elusive thing because, unlike most moths, it's not attracted to bright light. But this find means we might find some caterpillars around and that's something we haven't seen for a 100 years or more."
Dr Mike Dickison, curator of natural history at the Whanganui Regional Museum, said those taking part in the blitz included a handful of scientists and amateur natural history enthusiasts trying to find and record as many of the sanctuary's species as possible.
"They've had these bioblitzes in other parts of the country, but this is the first we've tried here at Bushy Park because there's so little known about the park's fauna.
They were out until late on Saturday night and then at it again from first light yesterday, bringing a vast number of species back to the scientists, who started processing what had been gathered.
Dr Dickison said the bioblitz meant they could create a species list for Bushy Park for the first time.
"There's lots already known about plants and birdlife in the park but to assess if the park has been harmed by predators, we need to look at the invertebrates, the small stuff that lives on the forest floor."
He said another blitz would be held 10 years from now to see what changes had happened.
"Some species can be identified straight away but entomologists will take weeks or months to work through what we've gathered. I wouldn't be surprised that we find one species that only lives here in Bushy Park," Dr Dickison said.
John Early, an entomologist at Auckland Museum, is no stranger to bioblitzes. He specialises in ants, bees and wasps.
"Most of what I've been finding is the small parasitic wasps that are typical to New Zealand bush," Mr Early said. "Initially, it appears that what I've got here is pretty typical of what you find in this type of bush." He said Bushy Park offered a spectacular piece of native forest which "is a treasure on your doorstep".