The population count

There are a few tools (other than using anecdotal information) used to estimate the population of kākāriki karaka in the Brook Waimārama Sanctuary. One is through monitoring changes in the birds detected in general sightings and on trailcams attached to feeders. It's a rough tool, but better than nothing. It should indicate significant change to the upside or downside.

A more accurate tool for counting the birds is to...... count them. We (Brook volunteers and staff) performed a count in September 2022. We used the playback method. The entire sanctuary is covered in a rough 300 x 300m grid. Personnel (working as individuals or pairs) play a previously-recorded kākāriki karaka soundtrack using mobile phone and bluetooth speaker at each point. Wait a minute, and play it again. The aim is to draw in any kākāriki karaka within hearing range. The operator attempts to count and identify all observed kākāriki karaka. When done, move onto the next point. Approximately 12 teams are used, and the intent is to cover the entire sanctuary in a day. One person or pair will usually do 7-10 playback points. Then repeat the entire operation within two days (ideally the following day). The number of birds detected forms the basis of the population estimate (after analysis for possible duplicates and/or missed birds etc).

We ended up with an estimated population of approximately 98 birds as of September 2022. A small reduction from the 104 translocated birds, but pretty successful given some of the recently-translocated birds had not yet had the opportunity to contribute to population growth.

We performed a population count again in July 2023, this time it was a joint DOC / Brook operation. The population estimate this time was 175 birds, representing population growth of about 40% from the 125 translocated birds. Needless to say everyone was extremely pleased, although not particularly surprised. It was nice to have 18 months of positive observations (nesting success, and random detections of unbanded sanctuary-born birds) and anecdotal information confirmed by scientific data. At this point, the Department of Conservation regard the kākāriki karaka population in the Brook as self-sustaining.

An unbanded kākāriki karaka detected during the playback survey