Category: Public Estate Diary

November 2013: In 2006/7 we helped Kate Steffens and her DOC team with funding for a trap line in the Fyfe river valley in south-east Kahurangi National Park.  At that time only two pairs of whio were known to be there.  DOC was then to carry on maintaining the line after our initial input. Kate reports that a May dog-assisted survey found 15 whio in the Fyfe valley, which included 6 pairs and 3 single adults.  Two of the adult males (Old Blue and Little Blue) seen were the original males from 2006.
The Fyfe is part of the Wangapeka/Fyfe whio security site which has a management objective of protecting 50 breeding pairs of whio by 2017.  This will be achieved by trapping for stoats along 70-90 km of waterway, carrying out aerial 1080 operations every 5-7 years, and boosting the population through the Whio Operation Nest Egg (WHIONE) program.
Monitoring of nesting success and adult survival during the nesting/moult period has shown that this population must contend with weka preying on eggs in the Wangapeka catchment and stoats, possums and rats ‘visiting’ whio nests.  At least one nesting female has been lost to predation, although the predator was not identified.

I think the concept of the whio security sites is a good one, given the huge breeding territories of these birds and the expensive trapping infrastructure needed. With finite money, concentrated effort in a few key sites is better than a piecemeal approach over their entire range.

In the early 1990s, kea were surveyed in the 6000 hectares around Lake Rotoiti, and there were 11 breeding pairs producing an average of 10 fledglings per year. By 2010, a survey over an expanded 13,000 hectares turned up only two breeding pairs. This is a classic problem with territories and total areas too large for affordable pest control. It’s quite reminiscent of the situation with whio/blue duck, where many km of trap lines are required to protect the range of a single pair. DOC’s Grant Harper and David Rees wanted to try localised pest control around nest sites: find the nests each season and move in with a perimeter of traps.

We bought some traps for the project, and nests were located and monitored with video cameras. In 2011 two of the three nests were cleaned out by possums. It was a similar story in 2012, with stoat predation being observed. This is not a happy outcome, but the idea is a good one and the team will keep trying, with help from a strong local conservation group, to stop another local extinction of kea.

Photo credit: Corey Mosen, DOC