National Geographic : 1969 Jul
their own osprey eyries. Several landowners fixed cart wheels atop poles for nesting sites, and when they lured a pair, they boasted as shamelessly as Rhinelanders with storks atop their chimneys.* But this agreeable picture changed alarm ingly. After two or three years, my wife Bar bara and I realized something was desperately wrong with our summer-resident ospreys. One July day in 1957, when Great Island should have been a scene of activity, with young birds at the flying stage, I scanned the marsh through my telescope. I saw the usual number of adults about-but where were the young? The nesting season obviously had been a failure. The next year confirmed my suspi cions. Although young ospreys ordinarily pip the shell in about five weeks, many adults sat on unhatched eggs for 60 to 70 days. Other eggs mysteriously disappeared. One bird brought a rubber ball to the nest and faith fully sat on it for six weeks! *See "White Storks, Vanishing Sentinels of the Roof tops," by Roger Tory Peterson, GEOGRAPHIC, June 1962. 56 To find out how bad the situation was, I consulted Peter Ames, who had begun studies of the Connecticut River osprey in 1957 while a graduate student in ornithology at Yale. "Reproduction is only a seventh to an eighth of what it should be," he reported. "The main problem is hatching, but plenty of eggs are disappearing too." "Egg collectors?" I asked. "I don't think so," Peter replied. "Could be raccoons." In 1962, with the aid of a grant from the National Geographic Society, Peter and my wife built 21 raccoon-proof nesting platforms, each about 39 inches square, mounted on 12 foot posts. Three-foot bands of sheet metal wrapped round the posts protected the nests from climbing animals. These platforms we ferried across the channel and erected through out the Great Island marsh (page 65). Many pairs that had nested on nearby duck blinds and on the ground switched to the safer sites. But production of young remained the same -sc arcely 13 percent of the norm. Finally we had several eggs analyzed.