Trumpeter swans, once nearly extinct in the lower 48, now winter at the confluence by the thousands The continent's biggest native waterfowl has been flocking to Riverlands Migratory Bird Sanctuaryâand winning a fanbase. Photography by Jennifer Silverberg In winter, about 10 phone calls a day come into the Audubon Center at the Riverlands Migratory Bird Sanctuary, near Alton, from folks hoping to see swans. âSome days, itâs nonstop,â says the centerâs executive director, Ken Buchholz, âand one of the first questions visitors ask when they walk in the center is âWhere are the swans today?ââ That is, trumpeter swansâ