The hippos had fled to other islands in the White Nile, driven away by one of the few forces that can dislodge a large herd of these fierce beasts — an even larger herd of elephants. And there they were: some 50 elephants, massive black figures peacefully grazing on their newly reclaimed territory on the Nile island of Opekoloe.

“To anyone who thought they’d disappeared forever, it’s like magic,” said Lt. Col. Charles Joseph, deputy warden of south Sudan’s Nimule national park near the border with Uganda, barely containing his excitement as he waded knee-deep through reed-filled water to approach the herd.

Sudan’s 22-year north-south civil war — Africa’s longest and bloodiest conflict, killed some two million people. It also drove out large numbers of animals.

Yes, and let’s remember who negotiated an end to the war: the Bush administration.

Now after two years of relative peace, they’re dramatically back. Wildlife services estimate 7,000 elephants have returned, along with some 1,500 giraffes and about 500 oryx antelopes, both thought to have left Sudan forever. Lions, leopards and a wide variety of gazelles, some of them unique to Sudan, are being spotted, too.

In a February aerial survey, the U.S.-based Wildlife Conservation Society estimated herds of antelope and gazelle numbered 1.3 million.

“It could well be the largest mammal migration on Earth,” said Paul Elkan, the society’s south Sudan country director.

I dunno. Ten million Americans moved to California during the 1980s.