Source: Environment Canterbury Regional Council
Heath said the high count of chicks to adults suggests that the Charwell site can offer a safer breeding ground compared to other monitored sites, where flooding and predation from mammalian and avian predators are major causes of nest failure, along with human interference. Predator control can help reduce predation, potentially increasing the chance of breeding success.
“Without our intervention here, it is likely that the karoro nesting alongside them would predate the tarāpuka chicks,” Heath said.
“Karoro predation has led to the complete failure of tarāpuka colonies at other Canterbury sites so it’s great we’ve been able to work with other agencies and the Kaikōura Men’s Shed to give the tarāpuka a better chance at breeding successfully.
“Coupled with weed control to maintain and increase suitable nesting habitat, we’re hoping to increase the odds for the breeding success for tarāpuka.”
The future of colony success
With the Charwell River free from the disruption of recreational access, or the challenge of high seas, Heath would like to see the Charwell River project remain a priority for North Canterbury. He encourages collaborations with DOC, LINZ and Te Rūnanga o Kaikōura to continue, alongside an increase in traps for the site, and continued focus on the control of karoro which, due to land use changes, have become super abundant and now threaten other river birds.
A weed management programme to protect the open gravel environments that our braided river birds depend on for nesting also makes Heath’s wishlist for the wider Tūtae Putaputa/Conway catchment, among other relatively weed-free sub-catchments.
“Long-term commitment by us and other agencies would greatly benefit this mahi at key sites for colony species: Waiau Toa hāpua and the rocky outcrops south, Upper Waiau Toa, Waiau Uwha and Hurunui,” he said.
“Collectively, we’re all responsible for taking care of tarāpuka and other braided river birds, and they need all the help that they can get to have any success in breeding in these wild, but highly modified environments.”
Header photo by Dan Burgin
