Tracking the birds

Over the next week or two, Department of Conservation staff from the Kākāriki karaka recovery programme (based in the DOC Rangiora Office) tracked the birds with radio trackers and trained Brook Waimārama Sanctuary volunteers and staff in the use of such equipment.

The birds spread out far and wide, as far west as Falcon Spur, down the valley to the north, east to the Upper Valley, and uphill to the south and over the fence (outside the sanctuary).

Transmitters are necessarily small (a few grams) and the batteries don't last longer than about six weeks. Over that six weeks the hope is that the birds will pair up and develop nesting instincts, and the birds will then lead us to some of their nests.

A DOC staff member with radio tracking device

Radio tracking involves selecting the frequency of a bird on the receiver, swinging the directional antenna side-to-side and looking for a signal, noting the direction, then moving on and picking it up again (or a few more times) and noting the changed direction. Triangulation is then used to narrow down a likely location. One then heads into the middle of the location (subject to geographical and vegetation hazards such as creeks, cliffs, bush-lawyer and onga-onga). Hopefully the signal strength increases and one can identify a tree that the bird is in. Full success comes from spotting the bird and confirming its identity from leg bands. Best possible scenario is it will have paired off and be showing interest in a potential nest hole.

Radio tracking can be a time-consuming business. One person finding two birds in a day would be considered a good outcome. Intent is to find every bird twice per week.