National Geographic : 1992 Nov
CENTER STAGE at a hack ing tower on the Ala bama River, immature eagles balance on perches (below right). A room in the back of the 12-by-24 -foot tower allows Sarah Gale and Marcus Koenen-who uncrated 13 birds weeks earlier (below)-to remain unseen as they feed and observe the eagles. They will do so for the next three months, ris ing before dawn to scatter the deck with whole fish and chunks of road-killed deer. There is no need to wean the eagles; instinct drives them to scavenge and hunt on their own. Two weeks after the birds' arrival the bars come down, and the birds-part of last year's crop of 54-test their wings, hopping between perches and flying to nearby trees. Bleach marks, like the one on the left wing of the bird below at far right, enable team members to identify individuals from an observation blind. Many flights, like a first bike ride, end in crash landings or tumbles to the ground. That is no place to lin ger, though, given threats like stray dogs and alligators, which claimed three eagles in 1989. One day the eagles will leave for good, beginning their north ern migration. Only about half will survive the trip and the ensuing winter. Yet many of those that do will return to within a hundred miles of their release sites; all five release states have reported sightings. More lasting evidence comes from Mississippi's Horn Island (right), where a six-year-old eagle brings fish to its nestling. The adult and its mate, both Sutton birds, have had offspring the past two years. Their nest was the first on the state's bar rier islands in some 50 years. Mated for life, the pair will build up the nest each breeding season, forming a structure so large it could eventually weigh two tons. Bald eagles, capable of living 30 years or more, create some of the world's biggest nests. Oklahoma also has, for the first time this century, two active nests of southern eagles.