In 2004 there was a 50% change of them going extinct. But they came back.
It wasn't easy (full details here). They had to remove feral pigs from the islands and relocate the Golden Eagles there. Originally there were Bald Eagles on the islands - but DDT decimated them. With most of the DDT out of the ecosystem, they relocated the Golden Eagles (which ate young foxes) and re-established the Bald Eagles (which don't much on the little critters).
The Channel Islands are both isolated AND close-ish to land AND small. So restoring the balance proved easier there than it might have been somewhere else. But it is great news.
The Channel Island Foxes are back (on Santa Rosa Island there were 15 left, now 1,700 are back!). The Bald Eagles are back and the ecosystem is getting back into balance.