"We were driving through Arthur's Pass and I saw a kea chewing on a car ... as they do. That's when I first became interested in the creatures."
Five years ago the survival status of keas fell to "nationally endangered" and Corey estimates there are about only 5000 of the birds remaining.
"The next stage is 'critical', which is the status of the kakapo at the moment," he said.
However, it wasn't always about the keas and, like many students leaving high school, he took "the leap" without knowing full well what his future career would entail.
"I studied for a bachelor of science degree, majoring in zoology at Massey in Palmerston North ... purely because that's what I was interested in.
"The course was great, it set me up with handy background info on animal behaviour and basic environmental knowledge."
After hitting the books he was eager to get stuck into real work.
"I volunteered in heaps of related fields, one being the national wildlife centre in the Wairarapa, Pukaha Mount Bruce."
Since then, he has volunteered all over the world - from rescuing sea turtles in the Greek Islands to working with endangered animals at the Grand Canyon, and has now set himself up as top-level biologist.
"I usually work intense hours over the summer months which enables me to do overseas volunteer projects during winter - I hate working in New Zealand over the winter because it gets insanely cold."
Corey bases himself in Nelson and can often be found with his dog, Ajax, and girlfriend Sarah in the bush land of Kahurangi National Park, northwest South Island.
For students contemplating a career helping endangered wildlife, he said volunteer work was definitely beneficial.
"It also helps you decide whether it's something you enjoy ... find something you love and then convince people to invest in you."
Tomorrow Corey will walk 14 kilometres to a hut in the Kahurangi National Park, and will then walk 1000 metres uphill and wander through more bush to check on a kea nest.
"I'm keeping an eye on two chicks nesting there and will check the camera I've set up to monitor them - as well as changing the battery.
"Long-term future? Who knows what's in store."