Veterinary professor Michael Lierz from JLU Gießen is helping to save New Zealand’s rare parrot species. His assisted reproduction procedure is already giving good results.
water . Walking calmly through the undergrowth with its relatively large claws, the kakapo offers a rather unusual, but at the same time amusing, sight. Native to New Zealand, the mossy green bird, which can grow up to 65 centimeters tall and weigh four kilograms, is the only known flightless parrot in the world. It got its name from the Maori, the natives of New Zealand. Translated into German, this is the night parrot. And, in fact, the kakapo roams its territory mainly at night. In general, it is rarely found in the wild because the bird is on the Red List and is one of the most endangered species in the world.
In the mid-1990s not even 50 living specimens were known. Things looked very bad for the kakapo for a long time. In the meantime, however, the number has risen again to more than 200. The fact that there are now regular offspring is also due to Gießen veterinarian Prof. Michael Lierz. The head of the clinic for birds, reptiles, amphibians and fish at Justus Liebig University (JLU) and his team have developed a procedure called assisted reproduction that now also benefits kakapos.
»In 2019, 70 chicks hatched. That is an absolute record,” Lierz reported in an interview with the indicator. In the more than two decades before that, even the “intensive protection measures” in the reserves and the individual care provided by rangers, which have continued to this day, would not have been as successful. But the night parrot doesn’t make it easy either, because it shows a very particular reproductive behaviour: “The kakapo only reproduces when the Rimu tree bears fruit every few years”, explains the researcher.
The females travel several kilometers to reach the courtship sites of the males, who call continuously throughout the night. To mate with them there and then take care of the eggs alone. They also cover these distances on foot, because the bird’s wings only serve to balance or to break the fall when jumping from a great height.
Although the kakapo’s plumage is actually well camouflaged in the wild, it helped little when humans invaded its habitat centuries ago, bringing with them cats, rats and other animals to hunt the flightless bird and its ground-nesting young. Although “widespread in New Zealand beforehand”, stocks were drastically decimated.
When the problem was finally recognized, steps were taken to make the areas where kakapos live in the wild, now only on New Zealand’s South Island, “completely free of predators”. The government is paying a lot to protect native parrot species. “The rangers constantly look after the kakapos and sometimes even sleep near them,” says Lierz. “All birds carry transmitters. That’s why you quickly realize when one of them is missing.«
Unfortunately, due to the corona pandemic and the long entry ban in New Zealand, Michael Lierz was unable to travel there again in 2020 and 2021. But he knows that the kakapos and their future offspring are in good hands. “During our last stay, we trained the rangers in assisted reproduction so that they can now perform this procedure themselves,” he reports. In this technique, sperm is collected from male birds either through massage or with the help of tiny electrical stimulation devices. The electricity used is so weak that the animals do not suffer any pain, says the scientist.
A female is then artificially inseminated with the sperm. In this way a broad genetic base is ensured, also so that there is no incest damage over the generations. “Studies also show that the fertilization rate of the eggs is much higher,” explains the veterinarian. Furthermore, if one of the males dies, “an entire genetic lineage could be broken.”
A maximum of four chicks hatch per clutch, but only every few years. Therefore, the eggs “are incubated in a machine for safety, to have a better chance of having more offspring.”
What was originally developed by Lierz and his colleagues in Germany to save rare species of large parrots is now being used for other endangered bird and reptile species as well. After presenting this method at an international conference a few years ago, “colleagues from New Zealand approached me to ask if the Kakapos could also be helped with it,” he says, recalling the beginnings of the cooperation. When the time should come not long after the next breeding cycle was due, the Giessen researcher spent several weeks in New Zealand with some employees.
This year, however, he will no longer be able to do so. The entry ban has since been lifted, but the most recent breeding cycle lasted “until March at the latest.” However, interim successes in increasing the numbers of adult and young birds make Michael Lierz confident that the kakapo population will continue to grow in the coming years and that this rare parrot can be saved from extinction.