Kākā – a conservation success story

Kākā (Nestor meridionalis) are one of New Zealand’s endemic parrots and a great example of how concerted efforts can improve a native species’ conservation status. It is estimated that there are about 10,000 kākā in New Zealand, spread across the three main islands, but particularly in forested areas, offshore islands and in or near wildlife sanctuaries. Land clearance of their forest habitat and introduced predators drastically reduced their numbers, but recent successful conservation efforts have seen their numbers grow. They are now classified as recovering, and in some areas such as Wellington, they are becoming a common sight.

Kākā are sometimes mistaken for their cousin, the cheeky alpine parrot kea, but kākā enjoy an arboreal lifestyle, generally living the high life in tall trees. Their colouring is more olive-brown rather than the olive-green of the kea, and when they take flight, you can see flashes of beautiful red-toned plumage under their wings. When flying in groups, you can often hear their “ka-aa” call. Like kea, kākā are intelligent and inquisitive birds.

Feeding

Kākā are one of the few sap-feeding birds in the world, but this behaviour can harm trees, as they rip bark off with their strong curved beaks to get to the sap underneath. Trees can also be damaged when kākā forage for invertebrates – such as the huhu beetle – as they remove bark and dig into the wood of live and dead trees. Wellington Botanic Garden staff have had to remove dying branches from some of their large exotic trees – such as eucalyptus and macrocarpa – to prevent them from falling due to the impact of kākā.

Kākā are an important pollinator for many of our native plants such as kōwhai, rātā and flax, as they use their brush-tipped tongue to access nectar from flowers. In the southern beech forests, honeydew is an important part of the diet of breeding birds, but kākā face competition from introduced pests, such as wasps.

Zealandia success

In June 2002, a few kākā were translocated into the ecosanctuary Zealandia in Wellington. This was the first time Wellingtonians had seen kākā in nearly a century. Over the next few years, more were added. Kākā flourished in the protected sanctuary and are now regarded as one of Zealandia’s biggest success stories. At the end of the 2018/19 breeding season, over 1,000 kākā had been banded and increasing numbers of wild kākā were showing up at Zealandia’s feeding sites – a clear sign that kākā were also breeding in natural nest sites both inside and outside Zealandia. In a 2018 interview with RNZ, Dr Danielle Shanahan from Zealandia, commented on the success of the sanctuary.

In Zealandia, we've seen an eight-fold increase in kākā, but also beyond the fence, we're seeing about double the kākā than 5 years ago, so we're seeing really rapid increases, and also how far they're distributed across the landscape as well.

Dr Danielle Shanahan, Zealandia

In 2016, the intensive nest box monitoring programme was scaled back, and Zealandia’s kākā population is now a source for translocations to other sanctuaries. In March 2016, Zealandia translocated 10 juvenile kākā to Cape Sanctuary in Hawke’s Bay.

Initially, each kākā was given leg bands with unique colour combinations. The different band colours allowed individual birds to be identified as well as the year (cohort). With the large and stable kākā population, banding is no longer regularly required.

There are also now large numbers of wild kākā around Pūkaha National Wildlife Centre in Wairarapa since the initial release of nine birds in 1996.

Learning to monitor kākā

Learning to look after these intelligent birds was a learning curve for all concerned at Zealandia. For example, the specially trained volunteers and staff discovered that they needed to change the original wooden nesting boxes to plastic nesting boxes. This was partly a cost decision, as kākā parents use their beaks to shred the inside of their nests to create shavings for the nest. It was just not economic to continually replace the large wooden nest boxes, so they were changed to blue plastic pipe ones, which get a new wood retrofit inside each year.

The observers learned to understand the breeding cycle of the kākā to help predict their behaviours and to know what might happen next. A standard kākā nest monitoring duty involves 1 hour of watching, observing and recording all activity – this means you have to be quiet and still (not a lot of fun when it’s wet). The goal is to identify the parents and wait for the mother to come off the nest, then very carefully check the eggs without disturbing the parents, looking to see how many eggs there are and to ensure none are broken. In the early days, eggs were candled to check fertility, but this has not been required for some time due to the kākā’s high breeding success.

A test subject

With over 1,000 banded birds, only some kākā need to be banded now and only when required for research projects. The nest boxes continue to be useful, not just for kākā to use, as they make it easier for researchers and trained volunteers to band new kākā and observe them.

One recent research project involved Victoria University Research Fellow Dr Rachael Shaw, who needed some of the kākā population banded for her bird cognition study. Rachael wants to use the research she undertook on the toutouwai (North Island robin) to see if it can also be applied to kākā. With the expansion of the kākā population into Wellington’s urban risk-filled environment, Rachael is looking to see if the behaviour of kākā can be modified by developing cognitive-based strategies to manipulate their behaviour, such as seeing if there are ways to discourage kākā from eating food that makes them sick.

Urban challenges

Most people are happy to see more of these cheerful birds in their city, but kākā are not used to an urban habitat. They face challenges such as physical objects like glass skyscrapers and getting the correct food. Urban kākā like to eat all sorts of things, much of which bears no similarity to their natural diet, for example, lead flashings on old roofs – lead tastes sweet but it is poisonous. They also like to eat wood or use it for nest building, but often they will use wood from houses and fences. Unfortunately, most of this type of wood is treated to make it last longer, meaning it contains toxic chemicals such as copper, chromium and arsenic.

The other way kākā are poisoned is by well meaning people feeding them foods such as nuts, grains and cheese – none of which are part of their natural diet. This has resulted in an increase in metabolic bone disease (MBD) in kākā chicks as they take regurgitated food from their parents. This disease prevents their bones from developing properly. Often there are no externally visible signs of MBD, but in serious cases, birds can have fatal beak and foot deformities. Please do not feed kākā. If you come across a sick kākā and it is outside a sanctuary, call the Department of Conservation.

Some sanctuaries, such as Zealandia, provide kākā with supplementary feeding stations, but this is to encourage them to anchor in a protected breeding area. This food is also safe and nutritious.

To encourage more kākā in your garden, try planting kākā-friendly plants such as kōwhai, five-finger and tree fuchsia and ensure you have kaka-resistant traps set to catch pest predators. If you have an older home, consider replacing lead nails and flashings that can be common in old roofs.

Kākā in the wild

Kākā observation is different in the wild. In a native forest, wild kākā are much more spread out, and it is likely that, with more predators, their behaviour is different. For example, kākā in protected areas might have more chicks as they do not have to compete for food and are at less risk from predators. Around sanctuaries such as Zealandia, the gender balance is pretty even. In the wild, females are predated more than males. This is because the females brood and nest in a cavity – making them easy prey for weasels, stoats and other pest predators.

It is unknown exactly how long kākā live for – as they are parrots, it is expected to be many decades. The Zealandia kākā who hatched in 2002 are still regarded as young. The speculation on lifespan is similar to kākāpō and tuatara – we just don’t yet have the experience to know.

With the Predator Free 2050 vision and ongoing kākā research, it is hoped that kākā numbers will continue to increase, particularly in the wild, and that humans and kākā will learn to coexist in harmony.