Visitation patterns of endangered grey parrots (Psittacus erithacus) in a forest clearing in the Democratic Republic of Congo.

Ariticle published on 16^th of August in the journal Ecology and Evolution, available for free here.

It’s 2021, Frederik and I live in the rainforest in DR Congo. We have been hired to study the biodiversity of the Nkuba Conservation Area. We are looking for projects we can carry out in the area to learn more about the wildlife of the rainforest. That is when we hear about groups of grey parrots (Psittacus erithacus) visiting a piece of land called Ungwe, located a day-walk from the Dian Fossey Gorilla Fund basis. According to the locals, parrots gather there in great numbers on the ground of a clearing every morning for a few hours. I prick my ears. I love parrots. And grey parrots usually spend time on top of the trees, not on the ground. I need to know more about that.

In the African rainforest, grey parrots have three main predators: big cats (like leopards), raptors, and humans. To be protected against these predators, the parrots mainly feed in small groups on top of the trees, where they can easily detect raptors and be out of reach of cats and men. The parrots in Ungwe must thus have a very good reason to gather on the ground of an open area, because they are particularly vulnerable there. Frederik and I decide to investigate. Luckily, we have a great team that can help us understand this puzzling behavior.

Launching the Parrot Project

The first step in scientific research is reviewing existing studies on the topic one wishes to study. So, I began reading all I could about wild grey parrots (Psittacus erithacus). The grey parrot is a bird particularly loved by pet-owners because of its ability to mimic human speech and has thus been extensively studied in captivity. But, as I soon found out, we know very little about the ecology and the behavior of the species in the wild. This is mainly because grey parrots live in remote African forests and are difficult to study as they keep flying around the forests. Going through what we call the grey literature – scientific reports that have not been peer-reviewed, I found some mentions of parrots landing in clearings in DRC, Cameroon and Central African Republic. Some scientists had thus observed the same thing happening in different places, but nobody knew how important this behavior was and why parrots would do it. There was no paper published on this behavior yet. It got more and more interesting.

The grey parrot used to be a very common species in the Congo Basin. Unfortunately, due to capture (for the pet trade) and forest clearing, it is now an endangered species. Millions of parrots are caught every year and shipped to other countries to be sold as pets, with most parrots dying during transport. In every clearing where parrots had been seen landing, scientists had also observed the presence of poachers capturing parrots. The clearing of Ungwe too was known to be used as a hunting ground by locals and there was thus a risk of poaching. We urgently needed to know more about how parrots used these clearings to make conservation recommendations for the species.

It was time to launch the Parrot Project. Frederik and I designed a protocol to observe the parrots in Ungwe so that we could answer a few basic questions:

• How often do parrots come to the clearing?
• How long do they stay?
• What do they do while they are on the ground?
• What factors influence the visitation patterns of the parrots in the clearing?

If we could answer these questions, we could know more about how important it is for parrots to visit the clearing (if they come often and stay long, the evolution theory says there must be a big advantage in doing so), why they come in the clearing and how to protect them.

The protocol was simple. Two members of the team, whom we will call the observers, would visit the clearing of Ungwe for a few days in a row every month. Of course, it would have been ideal to have observers present all year-round for many years, but for many reasons, this was not possible. Fieldwork is expensive and, in these regions, physically and mentally trying. So, we would settle for 90 days of observation spread across one year. This would give us a representative idea of what was going on.

The clearing of Ungwe is quite special. It is one of the very rare natural openings in the forests: there is no tree, the ground is covered with grasses, ferns and other water-loving plants. The clearing is some type of marsh, with lots of water in the ground. That means that it is impossible to camp near the clearing. The observers would thus head from the camp to the clearing every morning before sunset, (before the parrots arrived), and would hide in the forest around the clearing in a spot where they could observe the parrots without being seen by them. It would obviously not do to disturb the parrots who are afraid of people. Once the observers were settled, they would wait in silence and record all sorts of things happening in the clearing:

• The date and the weather.
• The time at which the first parrot arrived in the area, which means when the observers could hear the parrots for the first time. This is easy because grey parrots are very vocal and would perch in the trees and start singing.
• The time at which the first parrot would land on the ground of the clearing.
• Every ten minutes, the estimated number of parrots present on the ground of the clearing.
• Every ten minutes, when they were done counting the parrots, the observers would choose one parrot on the ground and watch it closely for five minutes (or until they lost the bird from sight) and record the time and what the parrot was doing (this could be eating, drinking, preening, mating, interacting with other parrots or moving around). This was very important because we could then know how much time the parrots would spend on each behavior per stretch of five minutes.
• The time at which all parrots had left the area.
• Whether there was something that would scare off the parrots.

We then used statistics to analyze the results and answer our different questions.

Results

Grey parrots come to the clearing almost every morning (almost 80% of the time). They come at dawn, around 06.00, and leave before noon. Every time, they follow a sort of ritual – they behaved in the same way. First, the parrots perched in the trees around the clearing and started singing. During roughly an hour, other parrots came from all directions to join the parrots in the trees and sing along. When that hour was up, one parrot would start flying over the clearing, one way then the other, every time closer to the ground, until it landed on the ground. Once the first parrot was landed, the other parrots joined him.

Once on the ground, the parrots stayed around one hour in the clearing. Thanks to the behavioral data recorded by the observers, we found that the main activity of parrots in the clearing is to eat. That is quite interesting because so far, scientists knew that parrots ate flowers, buds, fruits and even bark of trees, but it was never reported that they fed on plants like those present in the clearing.

Parrots come to the clearing in groups of around 40 parrots though the observers saw more than 150 parrots at the same time in Ungwe. And these are only estimations. The size of the group was probably even larger since the observers could not always see all the parrots at once and many parrots stayed in the trees while others were on the ground.

We noticed that if parrots see a bird of prey flying over, if they hear humans in the vicinity or if they would hear other birds giving an alarm call, they will immediately take off and leave the area. Most of the time, they did not return afterwards.

Finally, when coming to the clearing, parrots like it dry. We found that parrots come earlier and stay longer in the clearing during the dry seasons than during the wet seasons and that they come more often and stay longer in the clearing when it is not raining. The clearing was particularly attractive in July, when we observed the largest groups of parrots, the highest visit frequencies and the longest visits.

Conclusions

Clearings are important

Parrots visit the clearing of Ungwe almost every day, but exclusively in the morning. They perform the same ritual every time they visit, first perching around the clearing while singing, then having one parrot fly over the clearing then landing on the ground together. They stay for an hour during which they feed on the ground, occasionally drinking water and moving around. These findings are interesting because they confirm almost exactly observations made by other scientists in similar clearings in DRC, Cameroon and Central African Republic. The fact that parrots would behave in the same way in clearings located far away from each other suggests that visiting clearing is an important behaviour that plays a key role in the ecology of the entire species. There is something about the clearing that is interesting to parrots since they come almost every day. But what could it be?

That is where our behavioural observations help us. We saw that when in the clearing, parrots mainly spent their time eating things from the ground like plants and roots. The clearing is therefore an important food source for the parrots. They get in the clearing something they don’t get anywhere else in the forests: a wet soil with plants different from the fruits, seeds and flowers they usually eat in the trees. Unfortunately, because we had to hide far in the forest, we could not see whether parrots ate the stem of the plants, their roots or even the mud. None of the scientists who saw grey parrots in clearings knows exactly why parrots come to the clearing, and while one of them thinks they mainly come to drink, another witnessed parrots eating mud.

Mud-eating, also called geophagy, is common among many species on earth, and particularly among parrots and macaws in South America. There, different species of parrots gather in areas called ‘salt licks’ where they ingest soil. Researchers think parrots eat mud in licks because it has properties that help them digest their food, which often contains toxins, or to supplement their diets, which are poor in minerals like sodium or magnesium. It is thus possible that grey parrots have evolved the same technique in the rainforests of Africa! It is also possible that the plants of the clearing are nutritious and contain important minerals. We need more detailed observations to better understand what is going on in the clearings of the Congo Basin.

The more, the safer

Parrots visit the clearings in groups. And we found that during the dry seasons, when the groups are larger, the parrots stay longer. That is because larger groups are safer than smaller ones. Many parrots means many pairs of eyes checking around to detect potential predators before they have a chance to attack. And even if there is an attack, dozens of birds flying off at the same time could confuse the assailant who would not know which one to catch first, offering an extra protection to the parrots.

The largest group of parrots seen in Ungwe had more than 150 birds, but the average size of the group was 40 parrots. Other sightings in clearings in DRC and Cameroon mentioned hundreds of parrots a few years ago. It is impossible to know if there are naturally fewer parrots in Ungwe, for example because the area has less food available, but there is a possibility that the populations of parrots in Nkuba have been reduced by the effect of capture for the pet trade. Unfortunately, there has been parrot trapping in the Nkuba Conservation Area in the past, and it may still be occurring today.

Our recommendations to protect parrots in the wild

It is crucial to protect parrots from poachers in all the clearings they visit. To do so, scientists must work closely with local communities who know best about their forests. Like in Nkuba, locals could help locating the clearings that are visited by parrots and find out whether poachers are active in the area. To protect the parrots, it is important to raise awareness among locals about the importance of protecting biodiversity, but mainly to provide communities with alternative sources of income, so they do not need to rely on the trade of parrots to survive. If possible, it would be best to prevent human activities near the clearings between sunrise and noon so parrots can feed without being disturbed.

What next?

This project was so interesting, and Frederik and I had a lot of fun studying the parrots. We are happy to have published a peer-reviewed article showing how important clearings are for the parrots, and we hope this new knowledge will ultimately help protecting grey parrots. But of course, there is much more we need to know about why parrots visit these clearings! Do they eat the mud or the plants? Does the clearing contain minerals that are useful to the parrots? Do they behave the same in all clearings in the Congo Basin?

To answer these questions, it would be incredibly useful to study the water, soil and plant composition of the clearing in Ungwe and everywhere else such clearings can be identified. Unfortunately, these clearings are located so deep in the rainforest, it is almost impossible to find them and carry out advanced tests on water or soil composition. We hope that more scientists will look for them and will be able to find out more about these fascinating places that are so important to the endangered grey parrots.

This article was published in August 2024 in the journal Ecology and Evolution. If you want to know more about our study and grey parrots, you can access the article for free here.  It contains a full bibliography with the articles we used to write our paper, check them out!

Frederik and I were lucky enough to spend some time in Ungwe with the parrots. It was important to get there with the observers to test the protocol before launching the project officially. But it also meant seeing the parrots in the wild, which was a unique experience. Read all about it in our other post called “The Dance of the African Grey Parrots: A Stunning Rainforest Ritual”.

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