You are entirely welcome. It was a good question. I apologise for missing part of the question in my answer, namely that some birds do have very different males and females. Even humans can tell them apart at once. Some have different voices, such as cuckoos. (Male cuckoos have much louder calls that one can hear further away. )

When there is a difference between males and females, usually the males are the ones with more colourful feathers (for example goldfinches, weaver birds, peacocks, sunbirds, birds of paradise and so on). However, there are a few kinds of birds like phalaropes, in which the females court the males, and the females also are larger and more colourful than the males.

The world is full of wonderful living things. Sorry to sound sententious, but really, that is understatement on my part!  :-)