Kākāriki karaka - egg gathering

For much of this summer a few of us in the Brook Waimārama Sanctuary kākāriki karaka monitoring team have been searching for parakeet nests that may provide the breeding programme with eggs. In order for the disparate populations of this critically endangered species to maintain healthy genetic diversity there must be some cross breeding between the populations on occasion. The practical way of doing this is to occasionally gather eggs from one population, hatch the eggs and raise the young at Isaac Conservation and Wildlife Trust, the birds will then hopefully breed and their offspring can be translocated to the other populations of this species in New Zealand.

This was going to be a difficult task, as many factors needed to line up. Specifically:-

• The nest needed to contain birds born in the Sanctuary (unbanded birds)
• The nest would ideally be not too far from the Sanctuary fence for quick access to a vehicle for transport to Nelson airport
• The nest must be reachable through climbing by rope and jumars
• The nest bowl should be accessible from the entrance (so eggs could be removed with a scoop by the person up the tree)
• The nest must contain eggs, once the eggs have hatched it would be too late
• The eggs should be a similar age to eggs laid by an infertile pair at Isaac so the female's infertile eggs could be swapped for the fertile eggs.

Given all the above, I was in the Brook Waimārama Sanctuary on Saturday weekend before last looking for a new nest or two. One commonly-used nest site had not been recently checked since its last use (the previous nest fledged mid-January). I decided to check this one out, as it ticked all the boxes for easy egg retrieval (only 4m off the ground, and a nest bowl level with the entrance for easy egg removal, also only 20 minutes walk from one of the fence access points). Rather than spend an hour or two watching the hole for signs of activity, I decided to attach my mobile phone to a stick with rubber bands, set the video recording, and look for signs of activity in the nest. The video quality was very poor (completely out of focus), but voila! I saw eggs. A glimpse of the green feathers of one of our special rare parakeets was also clear. Here's a still from the video. I guessed at least five eggs. 

So I did a 'proper' nest watch. This involved watching the nest hole and waiting for the male to arrive and call the female off the nest for a feed (or any kind of activity at the nest). About 45 minutes later he arrived as expected, called out, she was out in a flash, and obviously hungry. That's her on the right. Note the feather loss on her chest, that's her brood patch.

Her feather loss is more apparent here, note the bare skin. This is to allow direct skin-to-egg contact for incubation, the eggs need to be kept at body temperature.

Also note the swollen cloaca, she's been recently laying.

After her feed, she nibbled on bark (and/or bugs?) for a few minutes then back into her nest.

Anyway, that all added up to a very good opportunity for egg retrieval. An unbanded pair, using an accessible nest, not far off the ground, with an accessible nest bowl, recent laying, and proof of eggs in the nest. So I emailed the information to the Department of Conservation Orange-Fronted Parakeet Recovery team. They had a meeting on Monday, and on Tuesday two of their crew drove from Rangiora to Nelson to collect some eggs from this nest.

On Wednesday the DoC crew roped the tree, climbed up and inspected the eggs. [The tree had been strung on a previous visit, this is achieved with a crossbow and a roll of string. The dart is fired over a branch above the nest, after several attempts the string goes where it's wanted, and tied off for potential future use. When it's time to climb the tree, a rope is pulled up by the string.] The eggs were analysed by light (shining a light through to observe developmental stage), and concluded the five eggs were 5 to 15 days old. This was four days after my mobile-phone-on-a-stick nest inspection, suggesting the eggs were 1 to 11 days old at the time.

On Thursday the DoC crew and a few other helpers (including me) visited again to retrieve the eggs. Initially Megan (DoC) climbed the tree to see if the female was in the nest (she was).

Preparing to jumar up the rope and inspect the nest.

Megan is at the nest entrance.

Then we waited for the male to arrive and call his mate off the nest for a feed. It is much safer to extract eggs with the female absent, eggs may become broken while attempting to take them out from under a brooding female. Unfortunately the male was not as cooperative this time as he was during my watch five days earlier. We waited. And waited. At one stage a kākāriki karaka landed in the mid-canopy near the nest entrance, but made no attempt to call off the female. Given where he landed it's very likely it was the male from the nest. Then he flew off.

At 11am the decision was made to climb the tree and attempt egg extraction with the female on the nest. We had been waiting for almost three hours. The eggs needed to be at Nelson airport by about 2pm and time was running out. Megan climbed the tree and attempted to extract the eggs.

Megan has moved off to the right of the nest entrance (the obvious slit in the trunk) as the female on several occasions appeared perhaps ready to leave the nest. She didn't.

After a few minutes up the tree and no success removing an egg from the nest, the male turned up! He landed on a branch a metre behind Megan briefly, then moved to the canopy five or so metres away. Our job suddenly changed. Our best option now was to be as small and quiet as possible and let the male call the female out of the nest. It had been over three hours (at least) since her last feed and she would definitely be hungry. Megan remained up the tree but the other humans on the ground stepped back to give the birds some space. Immediately the female came out and disappeared with her mate.

Megan shines a torch on a wire into the nest cavity.

All concentration as she attempts to scoop up an egg and remove it without damaging it.

Success. Megan transfers an egg into her hand then closes her hand gently but securely. She then transfers the egg to a container with cotton wool.

The container with the egg is put in a sack and sent down string on a pulley to the ground for immediate transfer to somewhere warm. In this case a human chest to maintain the egg at body temperature.

Megan arrived back on the ground after 52 minutes up the tree.

Mission accomplished. The last hour was a tense time for all. Mishaps must be avoided with this precious cargo. We were in a hurry by then, so the eggs were carried up the hill kept warm against human chests. This allowed faster transit. Upon arrival at the vehicle, the eggs were transferred to the incubator for the slow drive down a very bumpy 4WD track to the main road, then to the airport just in time for transport to Christchurch, then to Isaac. The inspection showed healthy, undamaged eggs, and by 6pm they were under the care of their infertile kākāriki karaka foster parent Daisy. The humans have done their job, now it's up to Daisy (and her mate) to finish the task and turn the eggs into fledglings and raise them to adulthood. They will then be genetically tested and in following seasons their genes will hopefully have propagated to other kākāriki karaka populations in New Zealand.