As adults, the low-quality females showed a preference for the songs of males of the same quality, and for the male birds themselves.

Evolutionary biologists previously thought that females would always opt for the best male available…

“The main reason, we think, could be that the two individuals just accept each other faster – they just go for it.

“The really amazing thing is that the females are able to recognise what ‘category’ they are in. We’d like to investigate further to find out how they do this.”