New Zealand's Green Parrots Escape Extinction, But Their Parasites Didn't

The Kākāpō: A Unique Bird with a Complex Relationship with Parasites

The kākāpō, a flightless parrot native to New Zealand, is one of the most unique and fascinating birds in the world. With its bright green feathers and round, owl-like face, it has captured the hearts of many. Its friendly nature and unusual behavior have even led to viral moments, such as when zoologist Mark Carwardine was mistaken for a female kākāpō. As the world’s heaviest parrot, it has become an unexpected media favorite.

However, not all creatures have such a positive reputation. Parasites, for example, are often seen as harmful and undesirable. Yet, scientists are beginning to understand that parasites may play a more significant role in ecosystems than previously thought. This includes their impact on the well-being of their host species.

In recent years, the population of the critically endangered kākāpō has shown signs of recovery, rising from near extinction. However, a new study published in Current Biology reveals that the parasites associated with these birds have not shared the same fate. Researchers are unsure what this means for the future of the kākāpō, but it raises important questions about the ecological balance.

Alexander Boast, a paleoecologist at the Bioeconomy Science Institute in New Zealand and lead author of the study, explains that even small or seemingly insignificant species can have a role in maintaining biodiversity. “Whether it’s a large, flightless parrot or a tapeworm, they all potentially have a role to play,” he says.

Marlene Zuk, an evolutionary biologist at the University of Minnesota, adds that parasites and their hosts often develop complex relationships over time. In some cases, these parasites may help animals, including humans, build stronger immune systems. They might also protect their hosts from more dangerous parasites.

In addition to this, parasites can contribute to biodiversity by preventing any single species from dominating an ecosystem. According to a statement from Manaaki Whenua-Landcare Research, a New Zealand-based organization involved in the study, parasites are increasingly recognized for their ecological importance.

To understand the diversity of parasites in the kākāpō, researchers analyzed over 200 droppings samples from the birds, some dating back more than 800 years. The kākāpō's unique behavior of pooping in cool, enclosed caves helped preserve these samples. More recent samples were either frozen or collected directly from the wild.

The study found that over 80% of the parasite groups once present in the kākāpō are no longer found in modern birds. Seven parasite species were identified that appear to be exclusive to the kākāpō, with four of them no longer existing in today’s population.

Once widespread across New Zealand, the kākāpō was nearly driven to extinction due to deforestation, hunting, and invasive predators. In 1995, there were only 51 kākāpō left in the wild. Although the population has since grown to around 241 birds on sanctuary islands, the species remains critically endangered.

Researchers suggest that the decline in parasite diversity may be linked to the kākāpō’s near extinction, which reduced the number of available hosts. Conservation efforts, such as deworming, could also have contributed to the loss of certain parasites.

Boast notes that this finding highlights how endangered species may only retain a fraction of their original parasite populations. While the full implications of this loss remain unclear, it underscores the need for further research into the complex relationships between hosts and parasites.

For now, the effects of the disappearance of these parasites on the kākāpō’s future are still uncertain. However, this study serves as a reminder that even the smallest creatures can have a significant impact on the health of an ecosystem.