Four protected kereru, or New Zealand pigeons, have been found shot dead at the Lake Mangamahoe Wildlife Sanctuary, near New Plymouth.
It's likely the birds were shot on October 9 when a neighbour heard gunshots in the area, Department of Conservation (DoC) ranger Wayne Beggs said.
A member of the public found the birds the next day.
They were near a picnic table beside the reserve's main access road, about 1.5km from the main entrance.
"The birds have been X-rayed and bullet fragments found indicate the weapon used was either a high-powered slug gun or a small calibre rifle," Mr Beggs said.
- Great Kereru Count almost done
- DoC want to catch campers keen to cook kereru
- Kereru shouldn't be 'eaten to extinction'
DoC is appealing for people with information to come forward.
Anybody who hunts or kills protected wildlife is liable to two years' imprisonment or a fine of up to $100,000, or both.