LOS ANGELES — In between morning feedings, the gibbons begin to sing — loudly. Ranging from the sound of emergency sirens and birds screeching to low grunts and guttural hoots, their vocalizations reverberate from a sanctuary in the hot, dry hills of the Santa Clarita Valley, north of Los Angeles. Over the past 50 years,
SOUTH KINGSTOWN, Rhode Island — On a pristine Rhode Island beach teeming with noisy seabirds, a group of biologists armed with nets sneak up on a pair of American oystercatcher chicks. But just as they close in to capture them, one of the football-sized birds, with bright orange beaks and long legs, runs toward a