PAINTING YOUR YARD PURPLE: Declining over parts of their range, purple martins need more help than ever from 'landlords' who install nest boxes for these highly social, insect-eating swallows

摘要

On a sultry summer evening, more than two dozen boats are anchored off a small island in Lake Murray, not far from Columbia, South Carolina. Their passengers are waiting to see one of nature's most amazing avian spectacles: a gathering of huge numbersof purple martins at a post-breeding roost. At first, only a handful of the dark, long-winged birds twitter high above the boats. Then, as the sun begins to set, their numbers build dramatically until tens of thousands of martins are circling over the island.