WHAT prompts different species of birds to join the dawn chorus at different times? Common redstarts, for example, kick off well before first light, but many of the early risers have already packed up by the time the tardy chaffinch joins in. Their start times are so predictable you could set your watch by them if dawn didn’t shift from day to day, says Tamás Székely at Bath University.
Székely and his colleagues report in a future issue of Proceedings of the Royal Society B that species with larger eyes tend to start singing earlier. Because the racket…
