BRINKLEY, Ark., April 28 - The ivory-billed woodpecker, a magnificent bird long given up for extinct, has been sighted in the cypress and tupelo swamp of the Cache River National Wildlife Refuge here in Arkansas, scientists announced Thursday. Bird experts, government agencies and conservation organizations involved kept the discovery secret for more than a year, while they worked to confirm the discovery and protect the bird's territory. Their announcement on Thursday brought rejoicing among birdwatchers, for whom the ivory bill has long been a holy grail - a creature that has been called the Lord God bird, apparently because that...