By the mid 70's things were about to change dramatically. The hunters had become so efficient they were shooting themselves out of a job.

From 1967 on, businessman Tim Wallis had exclusive hunting rights to all of Fiordland National Park and was taking out deer in their thousands.

Resentment from other operators at being excluded came to a head in 1973 in the so-called Helicopter Wars with constant poaching in the park. It went too far with helicopters being sabotaged and eventually the RNZAF stepped in to try and sort it out - to no avail.

But things were about to change dramatically again in the industry. The hunters had become so efficient they were in danger of shooting themselves out of a job. As deer numbers diminished it became uneconomic to keep flying and the end was in sight.

In desperation the industry tried their hand at live capture to set up deer farms. It was highly risky work at first. Leaping on running deer from a helicopter - known as bulldogging - or firing tranquiliser darts into animals. Each approach had its own problems of having to be so close to the animals - and the ground.

What saved the day was the invention of net guns. The first were very crude and took a terrible toll on the shooters with their savage recoil. Many a net was fired into the rotors or snagged on helicopter skids or tangled in bushes and crashes increased. Eventually more sophisticated guns were developed that the pilot could fire remotely.

Because of tax breaks for investors, the so-called "Queen Street farmers" got into the game, and the demand for live deer skyrocketed. The price of a hind rose from three or four hundred dollars to three, four and even five thousand dollars a beast. On a good run, pilot and shooter could make $10,000 before breakfast - unheard of money for the times.

Go to this episode on rnz.co.nz for more details