Vehicles racing through the Ashley River where endangered native birds are nesting. Photo / Grant Davey
Endangered native birds are at risk at a Canterbury braided river due to people recklessly driving through their nests.
The Ashley Rakahuri Rivercare Group works tirelessly to maintain the river and the wildlife that inhabits it.
Member Grant Davey said this year they have had the second biggest black-billed gull colony on the river in 20 years.
"We try to look after the birds that nest here. People see a group of the gulls and think 'oh they're just seagulls' but they're not.
"The black-billed gull is currently listed as nationally critically endangered."
That means they are in the most severely threatened group, facing an immediate high risk of extinction.
Environment Canterbury chair Jenny Hughey said they are the most endangered gull species in the world.
Last week 10 of the birds were killed by motorbike riders, she said.
"This is extremely disappointing and unacceptable behaviour, and we are exploring what our enforcement options are.
"These beautiful birds are unique to New Zealand, mainly breeding on South Island braided rivers. With current trends they would further decline of around 70 per cent over the next 30 years."
Davey said in recent months there have been about six separate incidents of motorbikes or four-wheeled drive vehicles driving into the birds' nests.
"Two motorbikes came racing through a group of young gulls and later I found a number of dead birds near that area. We can't prove it was the motorbikes but I think it was."
The group has motion-detecting trail cameras set-up at the river.
"Another incident recently we caught on camera was a four-wheeled drive which was driving straight up to the gulls and they all took off in a big cloud and the vehicle just kept going straight through it.
"There are still a number of young birds that can't fly yet."
Davey said the rivercare group and Environment Canterbury have been working to solve the problem for years.
They monitor the area closely, and there is signage installed along the river advising park users about the nesting area, and concrete blocks are installed at entry points to deter vehicles, Hughey said.
"The nesting area has been cordoned off since September to protect the colony, and will be open in two weeks when the birds have fledged.
The birds' nesting season usually runs from about July-February each year, Davey said.
Under the Wildlife Act, penalties for hunting, killing or disturbing absolutely protected wildlife can be up to five years imprisonment or a $300,000 fine.
"It is just reckless and absolutely unacceptable behaviour."
• If you see anyone disturbing the colonies contact ECan on 0800 324 636.
'It is a much more efficient way of getting twice as many apples using a lot less water.'