Tired kiwi laying smaller eggs?
Last year’s dry summer may have impacted the eggs that kiwi have been laying this year. Eggs retrieved in February and March by the Forest Lifeforce Restoration Trust’s Maungataniwha Kiwi Project were slower to arrive and smaller than in previous years, a change noticed in eggs from across the North Island by the Kiwi Encounter incubation facility at Rainbows Springs, Rotorua.
Kiwi generally lay their eggs in two clutches. The change in eggs from Maungataniwha was noticed in the second clutch.
This could mean that the birds are not in peak condition and are less keen to lay and sit,” said Claire Travers, husbandry manager at Kiwi Encounter. “This could be a result of the very dry summer last year, which meant fewer invertebrates were available for kiwi to eat.”
With only a couple of kiwi still sitting on their eggs the Maungataniwha Kiwi Project’s 2013/2014 season is drawing to a close. So far this season the Forest Lifeforce Restoration Trust has sent 43 eggs to Kiwi Encounter, 30 of which were viable.
There was one incubation death and the Kiwi Encounter team had to euthanase two chicks due to developmental abnormalities. The remaining 27 chicks are now in the predator-proof area at Cape Kidnappers south of Napier where they’re raised until they’re large enough to defend themselves in the wild, at which point they’ll be returned either to Maungataniwha, in inland Hawke’s Bay, or to partner conservation projects in order to widen the gene pool around a little.
So far the Trust has had the DNA feather results from just 15 of these chicks, showing six females and nine males. Trust forest manager Pete Shaw expects this to even out once all the results are in.
“Despite the changes the Kiwi Encounter team is noticing primarily in the second clutch, the first clutch of eggs from Maungataniwha this season resulted in the largest chick yet recorded at Kiwi Encounter,” Shaw said.
Called Fat Freddie after the kiwi band Fat Freddie’s Drop, this chick weighed 432g, nearly 100g heavier than an average kiwi chick at hatch. Fat Freddie was the second whopper to reach Kiwi Encounter from Maungataniwha. The previous record-holder, Big Norm, weighed 424.2g at hatch
The birds aren’t related and their sires’ territories don’t appear to share any similarities when mapped out. But Forest Lifeforce Restoration Trust staff are gathering data about the territories of males producing larger chicks in the hope that this might reveal habitat factors which influence offspring size and potentially nest success.
In addition to the Maungataniwha Kiwi Project the Trust runs a series of native flora and fauna regeneration projects.
These include a drive to increase the wild-grown population of Kakabeak (Clianthus maximus), an extremely rare type of shrub, and the re-establishment of native plants and forest on 4,000 hectares currently, or until recently, under pine.