It’s a stormy day in Fiordland.
With a potential break in the weather ahead, it might just be enough time for Department of Conservation science advisors Terry Greene and Emma Williams to race down from Christchurch and complete their mission: find and tag some elusive juvenile kākā.
Kākā, a large endemic parrot found in New Zealand native forests, are known for their boisterous personalities, amusing antics and raucous voices. On predator-free islands kākā clown around, screech, chatter, and are so confident around humans that they are often seen trying to unzip their backpacks and steal food.
On the mainland kākā are particularly vulnerable to predators because the female incubates her eggs for 50 days. A kākā population can be functionally extinct because all the females have been killed, and only males remain in a population.
In 2018, the Department of Conservation received funding through the budget to enable us to learn about mobile threatened species – those animals that are moving around so much it makes it hard to manage them in the wild. Species that are considered mobile move across entire regions or the country, often on a seasonal basis for food sources and breeding. With this new mobile species project comes the exciting new opportunity to trial satellite GPS transmitters.
This is great news for our threatened species. For years, rudimentary transmitters based on radio VHF signals have been the best technology available for tracking birds, and in order to get a fix on your bird you need to be within one kilometre. For an extremely mobile species like kākā which move across extensive forested areas high up in the canopy, the chances are that if you don’t know where they nest, you simply won’t find them again.
This issue is solved as global positioning systems (GPS) are finally small enough and affordable enough to put on smaller birds (under 700 grams). Devices are accurate worldwide within 15 metres. They can be pre-programmed for when you want to receive location fixes – hourly, daily, or monthly. This gives fine-scale insights into bird movements. These GPS fixes are then uploaded to a constellation of low Earth orbit satellites called Argos.
Thousands of animals are tracked with Argos transmitters, from European lynx to marine turtles. Argos enables biologists and scientists around the world to improve their understanding of animal behaviours such as movement, foraging, strategies, reproduction, and the way they adapt to their surrounding environment.
It’s the very first time we’re testing this technology on juvenile kākā. When kākā are fully grown adults, they nest in one place and are reasonably easy to find if you know their general nest sites. They also have a reputation for generally being heard before they’re seen, which helps.
While they’re juveniles, however, kākā do what teens in NZ have done for generations and fly off on a big OE to find themselves. They often don’t return to where they grew up, settling in other forested areas.
Being able to track juvenile kākā means we could learn their scale of seasonal movements as they follow different food sources across New Zealand. We could learn where they settle, and what time of the day they forage. Once we know more about what kākā need, we can invest in protecting it.
In order to fit a transmitter on a kākā, you need to do it before they fledge because they’re so mobile and, as DOC science advisor Emma Williams puts it, “frankly far too clever to recapture”. The sweet spot is around 50-55 days old – too young and they’re too small to fit a transmitter on. Kākā nest in hollow tree cavities up to 25 metres off the ground, so it’s time to go tree climbing.
Tree one has chicks but they’re too small for transmitters. The team still band them and do a quick health check but send them back to their nest to grow a bit more.
In Fiordland, Williams and Greene have ten trees to check. Starting with the tree most likely to have 50 day old chicks, Greene shimmies up the first tree (note: this is technically called a single rope tree climb – something all relevant DOC staff are expected to train and qualify at).
Tree two’s chicks have already fledged, and the nest is deserted.
Tree three’s nest is too deep inside the tree for the equipment to reach, so the chicks are left scurrying around on the nest below.
By the ninth tree, there isn’t a suitable kākā to fit a transmitter on and the weather is turning. The last trip didn’t manage it either, and the team are resigned to an incomplete mission.
Up the tenth tree, however, the team hits the unexpected jackpot: two near-fledging age juveniles. It’s hard to tell who is more surprised; Greene or the two kākā chicks blinking up at the frightening featherless face peering down at them. The chicks are full of personality. One is busy climbing up the walls of the nest boisterously trying to fly, and the other is very laid back. It’s likely the personality difference means the energetic one is older and closer to fledging.
Carefully bringing the kākā down to the ground in the specially developed travel bag that looks a little like Santa’s sack, the team set to work to put the GPS transmitters on the chicks.
The chicks are named after two satellites – Kepler and Kassini (that are in turn named after famous astronomers). Transmitters are attached leaving enough room to finish growing, Greene shimmies, Father Christmas-style, back up to their cavity and leaves the pair to wonder what on earth just happened.
Less than a week later, back in the DOC office a computer notification pings. It’s the first transmission from a tracker and it has gone off because one of the chicks is out of the tree, and going on his first flight.
Over the next 3 weeks DOC scientists continue to get fixes from the birds that show them roaming around their native forest playground, staying within 500 metres of the nest as the parents feed them. Like all teenage siblings, they give each other distance as they grow up.
Over the next three months it’s expected that each will move gradually further afield until eventually they leave the forest they grew up in and go explore New Zealand.
And thanks to their satellite transmitter, they’ll take us with them.