A failed kākāriki karaka nest

Sometimes things don't work out as well as we'd like. In the summer of 2022/2023 a pair of kākāriki karaka had a nest on a hillock above the aviaries. This nest was lower down than most (four metres off the ground) and we had hopes for watching hungry nestlings being fed at the nest entrance without the need for binoculars. Unfortunately the female likely had a cloacal prolapse, she disappeared one day in March 2023 and was never seen again. Over the next two weeks the male made repeated attempts to call her off her nest, it was distressing to see his distress. Eventually he gave up and re-paired.

Given this nest hole was accessible I managed to photograph (with my mobile phone on April 17th) the nest through the entrance. This photo shows at least seven unhatched eggs. They'd been scattered a bit by a kākāriki karaka unrelated to the nest, normally one would expect the eggs to be in a clutch for incubation. By this time the nest had been abandoned for several weeks.

Skip forward a season to November 2023, and other kākāriki karaka are showing signs of interest in this nest cavity. Bits of old eggshell have been discovered on the ground under the nest entrance over the last few months (scattered and broken during nest prospecting or nest preparation). Here, an intact (but old) egg has been rolled towards the nest entrance (photo from Nov 1st). Next time I went past this tree the egg was gone.

A kārearea flyby

September is the time to start checking out previously-used kākāriki karaka nest sites for possible re-use at the beginning of the main nesting season (September). I was watching a nest hole used in the last two seasons for signs of activity, when a pair of kārearea (NZ falcon) spiralled down from above, one landing on a branch a few metres off the ground, the other on the ground. One appeared to be holding a hefty rotten stick, I guessed it may have alighted on a branch that snapped under its weight, then for some reason refused to let go and spiralled down holding the stick.

Anyway, my focus changed from kākāriki karaka nest-watching to kārearea photography. As soon as I started clicking, the pair of them took flight and flew past me about one metre over my head. One landed on a branch about eight metres away, but the other landed on a log at about my head height two metres behind me. Kārearea are well known for dive-bombing intruders who get too close to their nest, and I initially thought that's what had happened. I subsequently worked out that there was nothing aggressive in their flyby, it was more likely curiosity. Other than the sound of their wings they were silent.

Here is one of them checking me out from two metres away.

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

More nests

The kākāriki karaka began nesting en-masse for the season in September. Then second nests in November. Then perhaps a third nest in January/February. Then perhaps birds who fledged in November may be ready for their first nest sometime in autumn (they may breed within 3-4 months of fledging).

We (OFP volunteers) worked out that the easiest way to find a nest is to watch a previously-used nest hole. There is a good chance the pair who used it last season will use it again this season. Pairs commonly have about three nest holes in circulation. They may start with nest 1, move onto 2, then onto 3, then go back to 1 for their fourth nest.

If a pair don't reuse a nest hole there is a decent chance some other pair will. They may have confidence it's a suitable site (they'll see signs of previous use) and make themselves at home.

Anyway, here's a favourite photo of mine from a nest watch. This is an unbanded pair using a previously used nest hole. The male had called the female off for a feed, here they are overhead courtship feeding. This photo was taken a long way overhead, at midday on a bright sunny day. The birds are in deep shade, and the blue reflects chromatic aberration in a cheap lens. I still like it. 😊

A nest was discovered today. A keen volunteer, James Davies, had finished the ranger course at the Nelson Polytechnic. He was keen on kākāriki karaka, and spent some time with us (Brook kākāriki volunteers). Today we were trying to find new nests (or second nests). James instinctively followed a bird 200m away from where he was watching, and waited. I caught up with him while he was having lunch, and almost immediately heard the sound of nestlings downhill. James went on to another nest watch and I moved downhill to where I'd heard the sound and waited. An hour later I heard the nestlings again, this time uphill! I moved back up, next time (an hour later) I heard them they were off to the side, and I quickly sighted a male feeding nestlings at the nest entrance. I went straight for video, and got a 30 second hand-held clip. It rained for the next few days, three days later I went back up with my tripod intending to film them properly but the nest was empty (the fledglings were in the canopy). If James had not followed his instincts we'd not have found this nest.  A team effort. James was subsequently employed by the Department of Conservation on the Kākāriki Karaka Recovery Programme.

The end of the translocations

March marked the final translocation (for now) of kākāriki karaka to the Brook Waimārama Sanctuary. All up, 125 birds have made the transition from captive breeding facilities to their introduced-predator-free original beech-forest habitat.

The reaction of the birds to their sudden freedom varied somewhat from release to release (and amongst individuals). Roughly, it went as follows:-

• Release 1 - They spread far and wide initially. I put this down to the fact that there were no other parakeets in the sanctuary on release, they perhaps went looking for members of their own species. When they found none some returned to the aviaries (and feeders), some paired off where they settled (e.g., the Upper Valley) and got on with nesting.

From Release 2 onwards, translocated birds had the advantage over the Release 1 birds of knowing prior to their release that they were in a parakeet-friendly location. They had spent their two days in the aviaries seeing and hearing the wild, resident parakeets outside chatting and using feeders. 

• Release 2 - They paired off quickly and got on with nesting.
• Release 3 & 4 - They were reasonably well grounded to the vicinity of the aviaries, but were a bit slow to pair off and nest.
• Release 5 - This group of birds were the most grounded of all. They were quite happy to stay in the vicinity of the aviaries/feeders.

The summer of 2022/2023 involved a partial beech mast, almost all of the regular feeder users from previous releases departed the feeders for a few months and ate plentiful natural food in the beech canopy.

• Release 6 & 7 -  These birds had little interest in feeders. Likely they went straight into the canopy and fed on plentiful natural food alongside the established population.

From whence cometh S-RO?

I was watching a potential nest hole, and a female arrived to enter the cavity. I had a clear view of her leg bands. Her ID was S-RO. I was immediately aware that this combination was unfamiliar to me, so I looked up the database to see what her story was. She did not exist! No such bird had been translocated to the Brook.

There were two possible explanations for this:-

• A banding error. When banded, her leg band combination had been incorrectly recorded. I looked through the database at undetected birds (parakeets released into the Brook who had not been seen since release), there are nine undetected females, but no combination is anything like Red over Orange. E.g., S-BG is undetected, perhaps someone erroneously recorded Blue over Green as Red over Orange. It seems unlikely, yet here she is..... or,

• A bird with this combination (S-RO) was last seen in the Hurunui Valley (inland Canterbury) three years earlier. Could she have flown 200 km north looking for more of her species, and stopped three years later when she found some in the Brook Waimārama Sanctuary?

The only possibility for solving this conundrum would be to find her again with better camera gear, and get close enough to record the numbers on her silver band on her left leg. It seems unlikely this will ever happen, so it's destined to remain a mystery.

Winter nests

Although the spring - summer - autumn season is the time for most of their nesting, kākāriki karaka can also breed over winter if food is in plentiful supply. We had evidence for seven nests beginning (laying) in April, May, July and August of 2022. None of the nests were found, but adult birds were subsequently spotted feeding fledglings, clear proof of successful nests!