Himalayan bird changes calls in response to tourism and traffic noise

Indian researchers have found that Himalayan monals are changing how they call out because of noise from tourists and traffic. The study, conducted over five years in Uttarakhand, showed that the birds are raising the pitch of their calls to be heard above human noise in busy valleys. The change is too small for people to notice, but recording devices can detect it. The shift is strongest at the top end of the bird's call range. Scientists say this is flexible behaviour, not a permanent change to the species. The birds are also moving to higher ground as their meadow habitat becomes crowded. Researchers warn that these vocal changes could affect how the birds find mates, though this has not yet been confirmed.