letting nature back in

In the nick of time before 2024 draws to a close, lets celebrate BirdLife South Africa’s Bird of the Year, the gorgeous eagle known as the bateleur. By championing an individual species each year, BirdLife South Africa hopes that the year-long information campaigns highlight the conservation importance of each named species and of South Africa’s amazing birdlife more generally. The bateleur is listed as an endangered species and so it needs all the help it can get.

Bateleurs (Terathopius ecaudatus) are medium-sized eagles and are more closely related to snake eagles than to true eagles and they also have a genetic link to vultures. Bateleurs are the only species in the genus; Terathopius refers to the bird’s marvellous or pretty face, and ecaudatus means “without a tail” as their tails are so short. With progressive moults into adult plumage the tail gets shorter still and so is especially short in adult birds, so much so that when in flight, the feet extend beyond the end of the tail. (See the stunning photo here of a bateleur in flight).

An adult female bateleur that I photographed near a small artificial watering point in the Mabuasehube Game Reserve in Botswana in the Kgalagadi Transfrontier Park

Bateleurs occur in most sub-Saharan African countries, except in the tropical rain forests of west and central Africa, and there may be a small population in the Arabian Peninsula. On occasion, vagrants may be seen outside the main parts of their range.

In South Africa, the range of bateleurs has contracted significantly over the past 100 years or so. Historically they occurred widely, even as far south as the southern Cape Province (Simmons), but bateleurs have been eradicated from most of their former range and now they only occur in protected areas. North of the Gariep/Orange River on the western side of the country they occur in protected areas such as the Kgalagadi Transfrontier Park, and northwards into Botswana. They also occur in the Kruger National Park and in the northern KwaZulu-Natal conservation areas of Hluhluwe-iMfolozi Park and iSimangaliso Wetland Park.

A bateleur peeping at us from its nest that is built in the fork of a tree that leans over a dirt road in the Mabuasehube Game Reserve in Botswana. We paused briefly below the nest and I took this photo through the windscreen before we slowly drove away

I have since learnt that bateleurs often abandon their nests if disturbed by human activity. With suitable trees being at a premium, perhaps the tree in the photo above was selected as a nesting site despite being over a road, or it was selected before the game reserve became more frequently visited. But then I see that the Wikipedia entry cites three sources that indicate that bateleurs may favour building nests near paths or roads! Bateleurs form lifelong monogamous pair bonds that extend over multiple breeding seasons and a pair will often go back to the same nesting site each year. Males and females share in the incubation of the single egg laid in each annual breeding season, and they share in the feeding and the raising of the chick.

Bateleurs prefer open woodlands and savannahs so long as there are trees suitable for nesting sites. They avoid dense forest, higher altitudes and deserts. In more arid regions such as in Namibia, they occur where there are tall woodlands near drainage lines or ephemeral rivers.

The silhouette of a bateleur in flight – the bowed wings are long relative to the length of the body and short tail. This female has nearly acquired full adult plumage colours. The reddish legs and feet don’t yet quite extend beyond the end of the tail, but after the next moult into adulthood the tail will be even shorter. Bateleurs spend up to 8 hours a day looking for food in a soaring low-altitude flight, though less so on overcast days

The common name “bateleur” was given to the bird by the French explorer, naturalist, collector and ornithologist François Levaillant (1753-1824). In French, the word means street entertainer, or more specifically acrobat, tumbler or tight-rope walker. It is thought this name was given on account of the bird’s sometimes acrobatic manoeuvres in flight or perhaps because it of its characteristic rocking motion of tilting from side to side when soaring, that could be thought similar to the rocking balancing motions of a tight-rope walker. Some flight embellishments or manoeuvres are part of ritualised nuptial aerial displays and also territorial displays, but as they also occur in juveniles, some flight embellishments may simply be in reaction to the presence of other bateleurs flying in the vicinity.

Even with online bird apps available, I still find my print Roberts Bird Guide useful. The illustrations for the bateleur (p.141) show the colour difference between the male and female adults, both when perched with folded wings and when in flight. The brown juvenile is also depicted, and an adult with wings spread as it “sunbathes” is also illustrated

Bateleurs are proficient diurnal hunters as well as sharp-eyed scavengers, often being the first species to show up at even small carcasses or carrion. They forage in flight and hunt and scavenge a variety of prey. Immature birds rely more on scavenging than adults who become more proficient at hunting, with small mammals being favoured prey, though birds and some reptiles are also hunted, and at times invertebrates are also taken.

An immature bateleur standing tall showing its distinctive large and cowled head, short legs and short tail. It is standing next to the remains of a small mammal carcass it has been eating. This bird has undergone at least one moult and is darker in colour than the paler brown of a juvenile. The wing tips are extending beyond the tail. The tail gets progressively shorter with each moult. It takes 7– 8 years to acquire full adult plumage, which is the age at which bateleurs reach sexual maturity. This photo was taken in Kruger National Park

It is not clear whether this bateleur hunted for itself what was possibly a hare. Initially, we saw a large brown eagle eating the carcass. It flew away and almost immediately the bateleur arrived to claim the carcass. As mentioned, immature bateleurs scavenge more than adults, but they are still capable of hunting. It is also known that bateleurs are frequently kleptoparasitised by tawny eagles – in other words, tawny eagles often nick the prey of bateleurs. We do not know which or indeed if either of these birds originally hunted the prey, or if both of them were scavenging successively from a found carcass

Above is the large brown eagle that we first saw with the prey animal. It could be a tawny eagle with the less common dark brown coloration, or it could be a steppe eagle. (The length of the gape is supposed to help distinguish between the two species, with the gape extending further below the eye in the steppe eagle, but I am not certain which it is from this photo.) It is interesting to compare the shape and profile of this eagle, with its smaller head relative to its body, to the shape of the bateleur

The bateleur grasping at the carcass as it prepares to tear off more bits to eat, showing its relatively short legs and robust feet with rough, tough skin, as is typical of snake eagles

The bateleur tearing at the carcass attracted the attention of several glossy starlings that were evidently hoping for morsels. While we there they did not venture too close

The only photos I have of a bateleur pair together were taken of a captive pair at the African Raptor Centre (https://africanraptor.co.za/) that is near Pietermaritzburg. Due to land invasions, the Centre relocated this year, from its previous premises to the Tala Collection Game Reserve also near Pietermaritzburg.

The pair, named Portia and Dartanian, are from different areas in Mpumalanga and each were brought to the centre after having been found injured and unable to fly. Although their lives were saved at the sanctuary, their injuries were such that they are not able to be rehabilitated for release back into the wild.

The breeding pair of bateleurs at the African Raptor Centre that provides rehabilitation and/or sanctuary to rescued raptors. In the photo above the male is on the left and the female (typically slightly larger) is on the right. The folded wings can be seen to extend way beyond the short tail

In captivity these two birds have become a breeding pair and have successfully bred, and to my knowledge at least two chicks have been born in captivity. Bateleurs lay a single egg. In the wild, both parents incubate the egg, and both contribute equally to brooding and feeding the chick. The chick develops slowly and first stands and engages in wing flapping at about 5 weeks. At about 6 weeks, it is able to feed itself when small prey is brought to the nest by the parent birds. It fledges only after 3 to 4 months, and returns to the nest after its first flights. It continues to return to the nest for about 3 months after its first flight and may remain dependent on its parents for as long as 4 months after fledging.

The pair engaged in a kind of bowing behaviour. Breeding pairs have a very close bond and in the wild often engage in behaviours such as allopreening that serve to strengthen their bond

With the breeding age of bateleurs only commencing at the age of 8 years, the fact that pairs only lay one egg per season, and that the development time from nesting to post-fledge requires investment from the parents for an exceptionally long time, being 8 to 9 months, the reproductive rate of bateleurs is very low. Rick Watson, who researched bateleurs in the Kruger National Park during the 1980s, found that bateleurs raise 0.47 young per pair per year. To be successful at maintaining population levels, breeding adults need to live a long a time. Even small declines in adult survival can be catastrophic for population levels.

After achieving independence, immature birds are driven out of the territory when the breeding season arrives, but they tend to return outside of the breeding/nesting season. Adopting a necessarily nomadic lifestyle, bateleurs, particularly immature birds, leave the relative safety of conservation areas. In a study in the Kruger National Park, recovered juveniles were found to have wandered between 30 to 285 km (18 to 177 miles). In this wandering, the eagles fly into adjacent stock-farming lands, where they become vulnerable to poisoning due to scavenging from baited carcasses that have been set out by farmers to target potential livestock predators, such as jackals.

We spent time observing the pairs’ bonding behaviour during a quiet time at the sanctuary when no other visitors were around

The beauty of the bateleur eagles is breathtaking as can be seen in this captive pair at the African Raptor Centre

It is tragic and shocking that in South Africa, according to BirdLife South Africa, bateleurs have had “an estimated population reduction of over 50% over the past three generations (40 years), leaving a regional population size of less than 1000 mature individuals” (https://www.birdlife.org.za/bird-of-the-year-2024/). In addition to extensive loss of habitat due to urbanisation, intensive agriculture and climate change, the tendency of bataleurs to scavenge has led to deaths of bateleurs over the last 100 years or so as a result of scavenging from poisoned carcasses, as has already been mentioned. Other causes of bateleur deaths include disturbances near nesting sites resulting in abandonment of chicks, individuals being killed when they fly into powerline cables, drown in farm reservoirs or are hit by motor vehicles when scavenging road kills. Illegal harvesting of birds for the traditional medicine trade is also a problem. In addition, the use of pesticides may also be contributing to the decline in bateleur numbers

In BirdLife International’s 2020 assessment, the status of bateleurs across their ranges in Africa was up-listed from Vulnerable to Endangered. According to the IUCN Red List of Threatened Species, threats facing bateleurs are summarised as follows:

Putative reasons for declines vary, but include poisoned baits, pesticides, trapping for international trade, nest disturbance from spreading human settlements, and increased intensification and degradation of agricultural land (Ferguson-Lees and Christie 2001, N. Baker in litt. 2005, S. Thomsett in litt. 2005). The major cause of the decline seems to be almost entirely poisoning by a few large-scale commercial farmers, but poisoning is also a problem in tribal small-stock farming communities. (https://www.iucnredlist.org/species/22695289/174413323)

Simmons writes that there is “virtually unanimous agreement” that the decrease in bateleurs is “owing to indiscrimate poisoning by livestock farmers, observing that on their own “pesticides in eggs and habitat destruction are unlikely to have reduced the range of the Bateleur” to the drastic extent that has occurred.

Even in captivity, this female bateleur demonstrates the sunbathing stance with wings spread that is typical of bateleurs

It is thought that bateleurs indulge in this type of sunbathing for thermoregulation purposes and/or to warm oils in the skin and feathers. The bird then spreads the warmed oils by preening so as to maintain the health of the feathers.

The sunbathing bateleur with wings spread viewed from the side

After sunning her front, the bird flopped forward onto her belly and, keeping her wings spread, she continued sunbathing. The impressive wingspan of about 1.8 metres (6 feet) can be appreciated as the bird lies on the ground, especially in contrast to her short body and almost non-existent tail

It is thought that this flopped-forward on the ground behaviour is adopted by bateleurs for the purposes of anting, that is allowing ants to crawl over the body to collect bits of skin and debris in the feathers. The theory is that when a bird is covered in ants it ruffles its feathers causing the ants to release formic acid in self-defence, which has the effect of ridding the birds of parasites! However, the bird we witnessed, albeit a captive bird, seemed merely to be extending her sunbathing behaviour.

A close-up of the female bateleur sunbathing

After only a few minutes of sunbathing, the bateleur was up and approached the birdbath in the enclosure. Bateleurs in the wild are known to spend a lot of time at water holes, often standing for long periods in the water, sometimes with wings outspread

The bateleur stepped into the water of the bird bath to drink. In this photo the bare red facial skin and the red skin of the feet look especially vivid.  Her stance in this photo conveys something of the power of these birds

And here she is still standing in the water while drinking

I wish I could strike a more optimistic note on the future of the bateleur eagles. BirdLife South Africa reports that the Bird of Prey Working Group of the Endangered Wildlife Trust has been active with an awareness and education programme for land-owners and stock farmers in Northern Cape, which has been successful in reducing the number of poisoning incidents, citing personal communication with AJ Botha. Such initiatives have the potential to benefit not only bateleurs but other eagles too as well as vultures.

The Endangered Wildlife Trust has also embarked on a research programme where individual bateleurs are tagged with GPS trackers, enabling conservationists to better understand the range covered by individuals bateleurs, especially important as immature bateleurs are known to roam widely over several hundred kilometres from where they were born and raised.

P.P.S. Positive Postscript

Going forward I hope to end each post by logging something positive. We all need to be able to acknowledge the hopeful in these times.

Above is a photo of a farm reservoir with a ramp extending into the water, which would enable birds and other creatures that are unfortunate enough to fall into the water to find a way out. It is not unusual for raptors to drown in farm reservoirs

Kudos to Hartnekskloof Guest Farm in the Tankwa Karoo for providing (even if the original intention was for something else?) an escape route in their farm reservoir. Hopefully, other owners of reservoirs do the same. (For more on Hartnekskloof Guest Farm see https://www.pressreader.com/south-africa/go-karoo-test/20240901/283386247201497)

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Wishing all readers and blogging friends hope, health and happiness in 2025

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Sources:

African Raptor Centre. https://africanraptor.co.za/

BirdLife South Africa. [n.d.] Introducing the Bateleur: Bird of the Year 2024. https://www.birdlife.org.za/bird-of-the-year-2024/

BirdLife International.  2020. Bateleur Terathopius ecaudatus. The IUCN Red List of Threatened Species. Version 2024-2https://www.iucnredlist.org/species/22695289/174413323

Chittenden, Hugh, Davies, Greg & Weiersbye, Ingrid. 2016. Roberts Bird Guide: Illustrating nearly 1,000 Species in Southern Africa (2^nd edition). Cape Town: Jacana.

Davies, Rob.  2010. The Bateleur – An Interview with Dr Rick Watson. African Raptors, https://www.africanraptors.org/the-bateleur-an-interview-with-dr-rick-watson/

Roberts VII Multimedia Birds of Southern Africa: PC Edition.  1997-2016 Southern

Taylor, Martin R. (Assessor). 2015. Terathopius ecaudatus. Redlist of South African Species. SANBI (South African National Biodiversity Institute). https://speciesstatus.sanbi.org/assessment/last-assessment/3187/

Simmons, R.E. [n.d.] Bateleur, Berghaan. Terathopius ecaudatus. From Southern African Bird Atlas Project (SABAP1) 1987-1991. Downloaded a pdf of the bateleur chapter at https://www.birdmap.africa/docs/sabap1/146.pdf

Wikipedia. 2024. Bateleur. https://en.wikipedia.org/wiki/Bateleur#:~:text=Description,-Close%2Dup%20of&text=The%20bateleur%20is%20of%20note,with%20a%20very%20large%20cere.

Posted by Carol