From early September to the end of January, threatened native birds like ngutu pare/wrybill, tūturiwhatu/banded dotterel, and tarāpuka/black-billed gull breed in the dynamic South Island braided rivers like the Ashley River/Rakahuri.
The Department of Conservation (DOC), Environment Canterbury, and Waimakariri District Council work together, alongside the community and other authorities, to manage the impacts of vehicles and other recreationists on the riverbed during nesting season.
DOC North Canterbury Operations Manager Leeann Ellis says these birds evolved to nest in the open river gravel and relied on camouflage to keep them safe from the native birds of prey, which were their only predators until introduced mammals arrived. This means they are vulnerable to disturbance and difficult for river users to spot.
"We know there are three sites with nesting birds in the upper stretch of the river (above the Okuku River confluence), which is managed by DOC, and we're asking drivers to please stay out of the riverbed during nesting season.
"In past years, a large number of vehicles have gathered on the Ashley River/Rakahuri for Crate Day and we're calling for people to go somewhere other than riverbeds if they must participate in Crate Day, or just wait until the nesting season is over in February."
Leeann Ellis says DOC is asking people to be responsible this year but if there are issues, we will need to look at options like blocking access or introducing bylaws prohibiting driving on the river at certain times of year.
"These native species are also fully protected and it's illegal to harm or kill them. Anyone found doing so could face a significant fine or even jail time."
The Ashley Rakahuri Rivercare Group (ARRG) formed in 1999 to protect riverbed birds and their habitat. They run an extensive trapping network, undertake community education and advocacy for the birds, weeding islands and monitoring and banding returning birds and new chicks.
ARRG's Judith Hughey says four-wheel-drive vehicles affect the survival chances of endangered braided river birds, and the group would be disappointed if vehicles gathered on the river for Crate Day again.
"Fast, noisy and aggressively driven vehicles can cause birds to abandon nests, kill chicks, smash eggs and leak contaminants in the river which could render the riverbed, shallows and the river itself unliveable for larvae, insects and small fish that birds rely on for their daily food."
The group works with Environment Canterbury, who have dedicated rangers monitoring the Ashley Rakahuri Regional Park area, to protect the part of the river that runs from the confluence of the Okuku River to the Ashley Rakahuri Estuary. Environment Canterbury and the ARRG install signage to inform park visitors about nesting birds. In the lead-up to nesting season, the organisations work together to install up to 150 concrete blocks at river access points to deter vehicles from driving on the riverbed.
"We have been pleased with how the vast majority of park visitors respect the nesting birds in areas downstream of the Okuku," says Parks and Forests Manager Chuck Dowdell. "It's now time to recognise the wider spread of nesting birds along the river and keep clear of all our braided rivers during nesting season."
Waimakariri District Council manage the campsite and picnic reserve at Ashley Gorge. Greenspace Manager Grant MacLeod says the council are concerned about drunk drivers unsafely driving past families picnicking and swimming at the gorge on Crate Day.
"This is a popular site and for visitors' safety, there's no access for unauthorised vehicles to get onto or off the river at the reserve."
Police will have a presence on the Ashley River/Rakahuri on Crate Day and are reminding drivers not to get behind the wheel after drinking, whether on the road or off.
Combined 4WD Club Chair Mike Sheppard says it's been disappointing to see some four-wheel-drivers behaving poorly in previous years as it reflects badly on responsible drivers.
"The club promotes responsible four-wheel-driving and works with land managers around access for their members and maintenance of tracks and facilities, and anti-social behaviour from drivers puts all of this at risk."
Braided rivers are an iconic feature of the South Island landscape. They are dynamic, globally rare rivers characterised by their many braids which change course regularly after weather events.
