Rare bird now thrives in tree farms
Even when John James Audubon first described the Swainson’s warbler in the 1830s, this small songbird bird was considered rare. While other birds from Audubon’s day, such as the ivory-billed woodpecker and the passenger pigeon, have now disappeared, this secretive warbler barely hung on, breeding in the dense underbrush of southeastern U.S. deciduous forests. Now, its populations are on the rise because the species is shifting where it spends its summers. Over the past 50 years, foresters in Texas, Louisiana, and other southeastern states have been planting rows of pines and harvesting them every 25 or so years. These plantations cover 16 million hectares, and biologists have called them biological deserts, thinking they support little wildlife. But following up on a report of Swainson’s warbler nests on one such tree plantation in Texas in the 1990s, Gary Graves, a Smithsonian Institution ornithologist who has studied this warbler for decades, has since 2008 found the bird in pine plantations in 10 states. The warbler thrives in young pine plantations, when the trees are still tightly packed and crowded with other bushes. Fortunately, because agroforesters rotate their plots, as the birds outgrow one section, there’s always a new one to settle into. By the turn of the next century, pine plantations could be the primary breeding ground for this bird, Graves reports online today in Bird Conservation International.