In 2015, for example, nearly 100,000 Ethiopians and Somalis traveled by boat to Yemen, one of the world's most dangerous countries. Last year, nearly 5,000 citizens of Congo, which is fighting powerful rebel groups, were seeking refuge in the Central African Republic, itself torn apart by civil war. And yet 10,000 Burundians have fled their country's own growing civil unrest for Congo. Thousands of Nigerians escaping the extremist Islamist group Boko Haram have gone to Chad, where different strains of that same insurgency conduct frequent deadly attacks.
A host of African nations find themselves in the tragic situation of watching citizens flee their borders as those from neighboring countries pour in seeking refuge. Sometimes, as in the case of South Sudan, that's because particular ethnic groups are targeted in their own countries but can find relative peace across the border. In Ethiopia, a disproportionate number of those fleeing to Yemen are from the Oromo ethnic group, which many say has faced persecution from the government.
Developing countries have long taken in a disproportionate number of the world's refugees — roughly 80 percent, according to the United Nations. But even for migration experts and relief workers, the willingness of refugees to leave one war for another is shocking. It's also proving an enormous challenge for humanitarian agencies, which are already overstretched and often not equipped to welcome refugees in countries that are still racked by conflict.
"People continue to arrive despite unprecedented escalated internal conflict in Yemen," U.N. spokesman Adrian Edwards said earlier this year.
The 43,000 South Sudanese who fled to Darfur this year are from the states of Northern Bahr El Ghazal and Warrap, and they are fleeing their homes because of "worsening food insecurity and ongoing conflict in the area," according to a U.N. statement. The country's conflict often involves an ethnic dimension, pitting Dinka and Nuer groups against each other, but there is also significant fighting over resources without regard to ethnicity.
In Darfur, where roughly 300,000 people have been killed since 2003, according to aid groups, the South Sudanese refugees have found little assistance. The United Nations reported that "no established mechanisms or resources were in place to receive and respond to a large influx."
That crisis is expected to worsen, and it's unclear how aid agencies, already overwhelmed in Darfur, will provide for an entirely new population of refugees. Though Darfur's crisis has received little attention in recent years, it has in some parts of the region grown worse.
"Despite ongoing peace efforts, recent years have witnessed an intensification of fighting in Darfur and, as a result, a deepening of the humanitarian crisis," said a statement from the United Nations Office for the Coordination of Humanitarian Affairs.
And now, another flow of refugees is on its way.
By the end of June, 100,000 South Sudanese refugees are expected to be in Darfur, the United Nations said.