Thousands of wildebeests have trotted back from Tanzania's Serengeti National Park to Maasai Mara Game Reserve, catching ecologists and park officials off guard.
The gnus moved from Kenya to Tanzania in September to breed and were not expected to return until April next year.
The animals usually spend three months in the Maasai Mara and nine months in the Serengeti but they have returned after two and 10 months respectively.
Mr Nicholas Murero, coordinator of the Mara-Serengeti ecosystem, told the Nation that this is the second such occurrence since 2015.
“In September, the wildebeests were supposed to still be in Maasai Mara but by then, they had started their return journey to Serengeti. Their return has brought concerns of a change in the pattern, leading to rescheduling of bookings by tourists who troop to the reserve annually to watch the spectacular migration,” said Mr Murero.
Ecologists speculate that challenges ranging from climate change, variation in land use in the Mara ecosystem, political and economic factors as well as human and cultural challenges disrupted the movement.
Mr Moses Kuyuoni, the chief warden at the reserve, said it is too early to comment but that preliminary observations show the change in weather patterns is the reason.
The warden added that the odd behaviour resulted in destruction of acres of vegetation and blocked the gnus migration corridor two months ago.
“Several factors have occasioned this. There is a lot of green grass regeneration in Maasai Mara due to rains. Many of the wildebeests didn’t cross in June due to disturbance by wild fires," he said by phone.
Mr Kuyuoni said conservationists in Kenya and Tanzania are monitoring the development.
He said many were surprised when the animals returned early to the Serengeti. As of late August, some wildebeests were seen in the northern part of the park and in the southern part of the Maasai Mara, around Sand River and in Trans-Mara.
According to a source at the Kenya Tourist Board (KTB), the change in the animal’s migration pattern calls for thorough investigations.
“I am aware of the wildebeests' late departure from the Serengeti to Maasai Mara, and the early return to Serengeti. Is this a climatic change phenomenon? Let the scientists find out,” the source said.
Mr Felix Migoya, of the Kenya Professional Safari Guides Association, said the change resulted in mixed feelings, with some regretting that clients who wanted to witness the migration early this month missed out.
The wildebeest migration attracts thousands of tourists every year, generating millions of dollars for both countries.
The wildebeest's life is an endless pilgrimage, a constant search for food and water. An estimated 400,000 of their calves are born during a six-week period early in the year — usually between late January and mid-March at Serengeti.
The annual event is so great a natural spectacle that it was named the eighth wonder of the world.
It is the world’s largest migration, involving more than two million animals in search of greener pastures in Kenya. It usually starts in July and ends in October.
The migration lights up tourism in the park and reserve, with the huffing and snorting of the animals kicking it off.