The Mega-Avi-Fauna of Africa: Kori Bustards (Ardeotis kori)

*Note: Text and all photos in all Kenya posts are by Shawn Billerman unless otherwise noted.

Africa is truly the land of megafauna, and these megafauna are not just limited to mammals; Africa is home to many very large species of birds, from the Ostrich (Struthio camelus), the largest extant bird, the Shoebill (Balaeniceps rex), a large, threatening stork-like bird with a massive bill, the Secretarybird (Sagittariius serpentarius), a bird of prey that stands nearly 1.3 meters (4 feet) tall, the Goliath Heron (Ardea goliath), the worlds largest heron standing at over 1.4 meters (4.5 feet), and the Kori Bustard (Ardeotis kori), which is arguably the heaviest flying bird (the Kori Bustard and the Great Bustard (Otis tarda) are very similarly sized, so the title of heaviest flying bird is difficult to give) (Wikipedia). The Kori Bustard is a member of the Bustard family (Otididae), a group of birds found throughout Africa, reaching into Europe and Asia. Bustards are currently placed in the order Gruiformes, which includes cranes (Family: Gruidae) and rails (Family: Rallidae). However, recent genetic work challenges this current classification, removing Otididae from Gruifomres, placing it as basal to a clade where Gruiformes and Cuculiformes are sister (Hackett et al. 2008).

Part of a phylogeny that shows the relationships between waterbirds. Note particularly the part of the tree including Gruiformes, Cuculiformes, and Otididae (Hackett et al. 2008). Branch I not well supported, but many branches within the clad are well supported (asterisks indicate ML values of 100%)

Bustards are birds of open grassland and bushland, and range in size from chicken and turkey sized birds, all the way up to Kori Bustard sized birds, measuring in at an average of 12.4 kg (26-27 lbs) and standing at 60-90 cm tall (2-3 feet). While I was in Kenya, I saw three species of bustards, the White-bellied (Eupodotis senegalensis) and Black-bellied Bustards (Eupodotis melanogaster), two medium sized bustards, and the Kori Bustard (Ardeotis kori). The Kori was one of my favorite birds that I saw while in Kenya, and I would like to share this short story of a particularly memorable encounter with one.

View of the "Black Cotton" habitat, dominated by Acacia drepanolobium, where we saw most of the Kori Bustards. "Black Cotton" is named for the black volcanic soil (visible in the road). This soil is quite different from most of Mpala, which is characterized by a red soil. The image above the Bustards is the remnants of an old cattle boma (traditional corral). This will eventually become a glade, which are extremely important to many mammal species for foraging and protection; Kori Bustard (Ardeotis kori) walking through Acacia drepanolobium; Kori Bustard (Ardeotis kori) (photo by Jess Marion)

After spending much of the day in the Black Cotton piloting our Acacia ant projects, Irby and Dustin took us to Baboon Cliffs Dam, a man-made watering hole that often had groups of drinking elephants, and some good waterbirds. On the pond, there were already large numbers (100’s) of Cattle Egret already roosting in the dense branches on the pond, as well as a few Long-tailed Cormorant, a pair of Little Grebe, as well as some Red-billed Teal and Yellow-billed Duck. There were also a fair number of weavers and Wattled Starlings coming into the Yellowfever trees to roost. After spending some time around the pond, and then on the cliffs enjoying the spectacular scenery, we decided it was time to go when some elephants and rain clouds got too close. Shortly after pulling away from the pond, I spotted Kori Bustard striding along the bare, red, rocky soil between Acacia bushes. Irby decided it was time to show the class how one of the world’s heaviest flying birds fly. We started driving toward the bustard, which just started running… we chased it around a lone Acacia for a good 30 seconds, us in the car, driving around in circles, the bustard running, on foot. Finally it just got fed up with the situation, and took flight with a good running start. There is only one word to describe the flight of that bird… wow… well, maybe two words… wow, and then, how!? My guess is that it only flew because it was tired of us. It clearly didn’t think we were much of a threat, since it only flew about 50 meters before landing again, looking back at us, and then continuing to forage. Watching the Kori Bustard in flight reminded me much of a swan in flight… a swan with a weight problem. Swans are very large birds, but they just don’t have the heft of a Kori Bustard. Later on in the trip, I was lucky enough to see a Kori Bustard fly again… at night. On one of our night drives, while maneuvering to get a better look at some Jackals, we spotted a Kori Bustard foraging in our spotlight. This bustard didn’t waste our time with a round-about chase around a bush, and just lifted up and took off into the darkness. Again, the same two words flashed in my head… but for some reason, this Kori Bustard wasn’t quite as impressive as the first. My only guess is that this one was a female, while the first was a male, which are quite a bit larger and heavier than females. But, who knows… perhaps it was just the darkness.

View from Baboon Cliffs

References:

Hackett, S.J., Kimball, R.T., Reddy, S., Bowie, R.C., Braun, E.L., Braun, M.J., Chojnowski, J.L., Cox, W.A., Han, K., Harshman, J., Huddleston, C.J., Marks, B.D., Miglia, K.J., Moore, W.S., Sheldon, F.H., Steadman, D.W., Witt, C.C., Yuri, T. (2008). A Phylogenomic Study of Birds Reveals Their Evolutionary History. Science, 320(5884), 1763-1768. DOI: 10.1126/science.1157704