The massive migration of 6 million antelopes from 4 species continues despite decades of war and instability.
A comprehensive aerial survey in South Sudan has revealed a huge migration of 6 million antelopes, marking the largest migration of land mammals on Earth. In comparison, the annual Great Migration between Tanzania and Kenya involves only about 2 million wildebeests, zebras, and gazelles, as reported by the Guardian on June 25.
A herd of tiang antelopes on their migration. (Photo: Marcus Westberg/African Parks).
“Estimates indicate that these herds are many times larger than the Great Migration. The actual scale is astonishing,” commented David Simpson, a manager at the non-profit organization African Parks. The herds of antelopes migrate through a region that remains resilient despite decades of civil war and instability in South Sudan.
In 2007, a survey by the Wildlife Conservation Society revealed that the migration in South Sudan included around 1.3 million animals. However, African Parks, which manages the Boma and Badingilo National Parks in southeastern South Sudan on behalf of the government, was able to provide a more accurate figure by utilizing advanced technology and conducting a more comprehensive assessment of the area. Two aircraft equipped with cameras were programmed to take photos every two seconds. A total of 330,000 images were analyzed by a team of experts at the University of Juba, using software to count the wildlife.
From April 28 to May 15, 2023, pilots and observers flew over an area of 122,774 square kilometers, nearly the size of Greece. This covered the entire known range of the antelope species in the Boma – Badingilo Jonglei region. They also examined some areas that had never been surveyed before. In addition to antelopes, the surveyors recorded many other species, including lions, giraffes, buffalo, and elephants.
“The most challenging part was setting up the aerial survey equipment in the aircraft to ensure the observation field was correct and calibrated accurately. Flying at low altitudes is extremely dangerous with large birds like hawks around the aircraft. Flying continuously for 4 hours each day for many weeks is very stressful,” shared Mike Fay, the coordinator of African Parks.
Estimates suggest there are 5 million white-eared kob, nearly 300,000 tiang antelopes, 350,000 Mongalla gazelles, and 160,000 bohor reedbucks, bringing the total for these 4 antelope species close to 6 million. According to Fay, this figure indicates that the migration of these antelopes is among the largest on Earth, surpassing any other mammal migration on the planet. This migration is a year-round movement of antelopes from southwest to northeast, entering Gambella in Ethiopia and back, possibly driven by food sources.
In the study, 126 animals from 12 species were fitted with collars to measure the distances they traveled. 11 white-eared kob, the most populous antelope species in the region, moved approximately 2,000 kilometers each. The migration in South Sudan is not the longest migration of land mammals; that record belongs to the caribou migration in Alaska, spanning 3,200 kilometers, but it is similar in distance to the migration between Tanzania and Kenya. Additionally, the number of animals in South Sudan is still smaller than the annual migration of 10 million straw-colored fruit bats, which fly from West Africa to Kasanka National Park.