Ecuadorian hummingbirds chirp ultrasonic songs of seduction
The unusually high-pitched songs may help the birds woo above background noises in their windy, mountain environment. (Paolo David Escobar/Neoselva Photography via AP)WASHINGTON Perched on a flowering shrub on a windy Andean mountainside, the tiny Ecuadorian Hillstar hummingbird chirps songs of seduction that only another bird of its kind can hear. For the new study, scientists climbed into the Ecuadorian Andes to reach high grasslands called paramos and locate the Hillstars breeding grounds. Humans can hear pitches up to about 20 kilohertz, but lose sensitivity to high-pitch sounds with age. During fieldwork, the younger scientists could usually hear the Hillstar hummingbird songs, but the older participants couldnt, Duque said.