The return from the brink of extinction: conservation success stories from New Zealand

By Lisa Horn

The environmental news is often a depressing onslaught of story after story about record-setting fires, killer storms, and the unprecedented loss of biodiversity around the globe. We could all use a dose of good news every now and then.

New Zealand is perhaps best known for its beautiful natural landscapes (think The Lord of the Rings) and kiwi (both the fruit and the bird). But, amongst environmentalists, New Zealand is also known as a pioneer in endangered species conservation.

Like many archipelagos around the world, New Zealand’s flora and fauna have evolved in isolation and many of these species are unique and found no where else on earth. Sadly, its amazing biodiversity was decimated when Europeans settled on the islands. Forests were replaced by farms and sheep. Non-native species, brought along both intentionally and unintentionally, wreaked havoc on the ecosystems. What makes this country unique, however, is that they’ve made extensive efforts to turn this story of destruction around.

Not all of New Zealand’s conservation success stories follow the same plot-line. There are, of course, different characters and challenges. What they share is that they inspire us to persevere and not give up, even when a species seems doomed to extinction. Some of New Zealand’s important conservation successes are celebrated in a recent paper published in the Journal of the Royal Society of New Zealand. Let’s follow the dramatic return of the North Island saddleback and the Mercury Islands tusked weta from the brink of extinction.

North Island saddleback (Philesturnus rufusater)

Saddlebacks are inquisitive, robin-sized birds. According to Maori legend, their chestnut-coloured saddle is a remnant of a scorch mark from the hands of the demi-god Maui, obtained when the disobedient bird refused to bring him water.

The North Island saddleback now lives in forests on over a dozen of New Zealand islands. Photo: Rob Lynch

Although they were once common on the mainland prior to the arrival of Europeans, all that was left of the North Island saddlebacks by the twentieth century was one population of around 500 birds on a single island. One catastrophic event could have wiped them out for good. In the 1920s, scientists decided that establishing new populations of saddlebacks on other islands would help to protect the species from extinction (equivalent to the old adage of not putting all your eggs in one basket). This process of capturing, transporting, and releasing an animal in a new place is an important tool in conservation biology called translocation.

It might seem odd to transport an animal like a bird to a different island and expect it to stay there. Wouldn’t it just fly back to where it came from? Apparently, some of the reasons contributing to the saddlebacks’ decline also made it a good candidate for translocation. Being relatively weak flyers which spend a lot of time at or near the forest floor, it is perhaps no surprise that they would become easy prey to introduced weasels, rodents, and cats in search of a meal. But this poor flying ability also meant they would not disperse from their new island home.

The saddleback females roost in cavities, making them perfect targets for egg predators. Photo: Dick Veitch

Hopes of establishing these new populations were shattered when these initial attempts, and subsequent attempts, failed. Being captured, contained and transported can be an extremely stressful experience for a wild bird, and saddlebacks were dying as a result. It was also quite likely they were being predated in their new homes, or that habitat at these release locations wasn’t as great as originally thought.

These failures led the recovery team to the realization that they were missing a piece of the puzzle. They needed to do research on the saddleback to figure out what wasn’t working. And so, they carried out a suite of studies on the basic ecology and habitat needs of the birds, allowing them to choose better release locations. They also improved the methods to capture, contain, and transport the birds, helping to make the whole translocation experience less stressful.

Finally, in 1964, scientists succeeded in their efforts to translocate the North Island saddleback. If these dedicated scientists had given up in the face of failure, who knows what the future would have held for these birds. Instead, the North Island saddleback has now been successfully established on more than 19 islands and has a much better chance of long-term survival than it did 100 years ago.

 

Mercury Islands tusked weta (Motuweta isolata)

It’s quite possible you’ve never heard of the Mercury Islands tusked weta, and maybe were wondering what type of creature it might be. As it turns out, it’s a flightless, cricket-like, carnivorous insect that’s nearly the size of your palm.

An adult male Mercury Island tusked weta. Only the males have the large tusks on their heads. Photo: Colin Miskelly, Te Papa

Scientists suspect that the Mercury Islands tusked weta was probably found on several different islands at some point in the past but was wiped out by introduced insect-eating rats. It had only survived on a single, rat-free island called Middle Island. With an already restricted range and an unexplained rapid decline in its numbers, very few individuals of this threatened species were left. If the rats arrived on Middle Island as well, there wouldn’t be much hope left for the tusked weta.

New Zealand’s Department of Conservation got to work on a plan to protect the tusked weta from probable extinction. They believed they could safeguard the weta by establishing new independent populations on neighbouring rat-free islands. There was, however, one major challenge. The tusked weta had become so scarce that there were too few left in the wild to transport to other islands. So, instead, a conservation-breeding program was established, relying on the reproductive prowess of only one male and two females taken from the wild.

The captive-breeding program was a huge success. It produced a large number of young weta making translocations to other islands possible. The young were released in the wild but protected by large cages, allowing scientists to continue to monitor them.

Wetas live on the forest floors on some of New Zealand’s rehabilitated and rodent-free islands. Photo: Colin Miskelly, Te Papa

Today, the few lonely tusked weta on Middle Island have transformed into well-established populations on five different islands. It’s worth noting that a certain amount of luck probably played a role in this story. The three weta, which helped kick-off the captive-breeding program, were amongst the last seen on Middle Island. Despite intensive monitoring, none have been found there since 2001. If those three weta hadn’t survived in the lab, or if the captive-breeding program hadn’t been immediately successful, this story could have had a dramatically different ending.

 

 

The take-home message:

Without dedicated and persistent conservation actions, the Mercury Islands tusked weta and the North Island saddleback would not have made their return from the brink of extinction. Instead, their dramatic stories show that with timely action and perseverance, we can save species that otherwise seem doomed to extinction.

New Zealand may seem far away from our conservation work here in Canada, but the lessons learned on the small islands in the south pacific are still applicable to endangered animals on the large North American continent. In Ontario, populations of eastern loggerhead shrikes or Massasauga rattlesnakes are found in small pockets just like the isolated populations of weta or saddlebacks on the New Zealand islands. Conservation-breeding and translocations are important techniques that we use in our recovery programs with shrikes, rattlesnakes, and other at-risk species here in Canada, and inspirational success stories from “down under” will encourage us to continue on the long and important road to recovery.

 


Nelson NJ, Briskie JV, Constantine R, Monks J, Wallis G, Watts C, and Wotton DM. 2018. The winners: species that have benefited from 30 years of conservation action. Journal of the Royal Society of New Zealand.

Get access to the published paper 


Lisa Horn

Lisa Horn

Guest Blogger – MSc Candidate at York University in the Stutchbury Lab

Lisa is an ecologist with a passion for wildlife and conservation. Lisa has wide-ranging experience in conducting ecological inventories, assessing environmental impact of proposed developments, and navigating the framework of environmental legislation. She has a special interest in ornithology and species at risk and is currently investigating the effects of climate change in wintering habitats of migratory songbirds on their arrival condition in Ontario.