Hawke's Bay kiwi had a dry spell of their own during the recent drought.
Local experts say a drop in egg numbers indicates the national bird turned its back on romance, preventing a second clutch of eggs this season.
More than half of the kiwi in one of the country's most prolific conservation initiatives failed to build second-clutch nests or produce an expected second set of viable eggs in the 2019/2020 breeding season. As a result, the Maungataniwha Kiwi Programme, run by the Forest Lifeforce Restoration Trust at its property in inland Hawke's Bay, delivered 46 viable eggs to the National Kiwi Hatchery in Rotorua, down from 62 in the previous season.
Staffers at the trust's property in the Maungataniwha Native Forest monitored 43 male birds during this season, three more than in the previous year. The birds produced a similar number of first-clutch nests that delivered viable eggs compared with the 2018/2019 season, but only seven successful second-clutch nests compared with 18 previously.
Some males abandoned their second-clutch nests in the early stages of incubation, or were not detected to nest at all.
The results were echoed by other kiwi conservation initiatives across the North Island, according to the National Kiwi Hatchery. It incubated 125 eggs during the season, only 21 of which were second-clutch eggs. Manager Emma Bean said the notable downturn in second-clutch nesting and egg production was likely due to extraordinarily dry conditions across the region in November last year.
"We believe that their failure to propagate was an instinctive reaction to the conditions at the time," Bean said. "Having produced a first clutch, their need to look after themselves outweighed their need to produce a second clutch, and so that's what they did."
Forest Lifeforce Restoration Trust staffer Barry Crene, who oversees the Maungataniwha Kiwi Programme, agreed.
"It was very dry at Maungataniwha," he said. "We found more kiwi than normal living nearer the streams or in muddy conditions."
The dry conditions also impacted the number of juvenile kiwi who were able to survive "creching", the part of the conservation process where young birds are released into predator-proof areas to live and grow until they are large enough to fend for themselves and can be released back into the wild.
Of the 46 viable eggs collected as part of the Maungataniwha Kiwi Programme, 29 (63 per cent) resulted in birds reared to a size where they could safely be released back into forests.
This contrasts starkly with the 5 per cent chance that kiwi have of making it to adulthood if their eggs are left in the bush unprotected against predators.
The egg-recovery work is part of the nationwide Operation Nest Egg (ONE) initiative, where they're retrieved from nests, then incubated and hatched under specialist care.
Most of the Maungataniwha Kiwi Programme's chicks from the 2019/2020 season were reared within a predator-proof enclosure at Cape Sanctuary, which employs two full-time kiwi staff, trappers and a project manager specifically to enable this work.
About a third were reared at the National Kiwi Hatchery due to the dry conditions in Hawke's Bay. They stay here until they are large enough to fend for themselves and can be released back into the wild.
Not all kiwi taken from Maungataniwha as eggs make their way back to that forest. Previously some have been released at Cape Sanctuary, Otanewainuku, the Whirinaki, the Kaweka Ranges and into captive breeding programmes.
All of the surviving Maungataniwha kiwi from the 2019/2020 season were released either there or on the trust's nearby 11,400ha Pohokura property.
Last year it detailed a $411,000 plan to re-establish a viable population of kiwi at Pohokura by releasing up to 200 birds there between 2019 and 2024.
The Forest Lifeforce Restoration Trust has carved out a name for itself as one of the most successful kiwi conservation initiatives in the country. But the trust's forest manager Pete Shaw said its work with kiwi could not happen without the help and investment from its conservation partners, particularly the Cape Sanctuary, the National Kiwi Hatchery and its funder Ngāi Tahu, the Department of Conservation and Kiwis for kiwi, the only national charity dedicated to protecting kiwi.
"This is absolutely a partnership of equals," Shaw said. "The complex equation that lets us all grow heaps of young kiwi to put back into our forests just wouldn't work if one of the elements wasn't there."