Kiwi habitats under threat from climate change
more habitat. On one hand, it’s getting too dry to probe, but on the other hand, there may be more surface insects.’’
Kiwi were highly territorial in Russell, where a pair had locked down about six hectares just for themselves, he said.
‘‘The bush is now full of these territorial birds, and to establish new territories, young birds need to disperse out of the forest to find new, unoccupied land.’’
At Trounson Kauri Park, north of Dargaville, kiwi, which are nocturnal, have been spotted searching for food during the daytime.
Colbourne said that if eastern parts of New Zealand got progressively drier, kiwi would retreat to the west. Alternatively, higher sea temperatures in the Tasman Sea could produce more evaporation and rainfall, which could extend kiwi distribution, given that the birds liked moister areas.
Warmer temperatures in the north could encourage more invertebrate pests, such as locusts, which were present in New Zealand but not yet in large proportions, he said.
He said the black beetle, a favoured kiwi food item in pastures surrounding bush, would likely extend its distribution further south.
If it was very dry, invertebrates would be much further down in the soil, and difficult for kiwi to catch, Colbourne said.
Irrigating the soil could help kiwis probe, but they had such large territories that it might have to take place over many hectares of bush per pair, he said.
Climate change wasn’t DOC’s biggest concern, he said – stoats were. ‘‘Drier areas may favour rabbits and hares, which in turn may encourage more ferrets, which can decimate kiwi populations.’’