An Australasian harrier/kāhu was tracked travelling between Otago and Waikato. PHOTO: SUPPLIED
The adult male left Whangamarino Wetland on September 26, soared across Cook Strait at heights of up to 300m and flew down the eastern South Island to arrive in Middlemarch on October 7, where he has stayed put.
The native bird is known to disperse over large areas, but its journey has not been GPS-tracked and documented until now.
Doc technical adviser Thomas Emmitt said the early results of the tracking were exciting.
"We've seen an adult male take a one-way trip covering 1600km from Whangamarino to Middlemarch, where he may have paired up to breed."
It was an impressive flight, Mr Emmitt said.
"We've also seen a young female fly 150km between the St James Conservation Area and Hororata in Canterbury three times in just over a month.
"She seems to have settled in Hororata for now."
It was thought these birds were dispersing to new territories and further monitoring would show whether they stayed in these locations, he said.
Doc was monitoring kāhu as part of research to better understand how the bird used the environment and interacted with threatened native bird species, which it sometimes preyed on.
"However, we don't know the extent to which kāhu impact threatened species populations.
"This research will help us understand whether we need to further protect these species from kāhu as part of wider conservation efforts."
Other tagged kāhu were staying more local and their flight paths showed a crisscross of movements and habitat uses.
The GPS tracking recorded finer-scale movements than previous studies and it was hoped analysis of this data would help shed light on kāhu interactions with threatened native species, he said.
Doc is undertaking the kāhu research in the Waikato, where there are bittern, and the Clarence River where there are black-fronted tern.
Both are critically endangered. - APL
