Gatherings of angels

"The migration of birds has for centuries amazed and confounded onlookers. Those fortunate enough to have witnessed the skies filling with these intrepid travelers wonder, how do they find their way to their destination? How do they withstand the dangers and rigors of their long-distance flight? Gatherings of Angels offers firsthand accounts by leading experts in avian migration who convey not only the biology but also a sense of the beauty and excitement that attend this most extraordinary of natural spectacles."--BOOK JACKET.