An Asia Koel (Female)

Day 021 of Our Winter:  The term sexual dimorphism is not some type of kinky behavior. It simply means when males and females of a species look different. Humans do seem to try hard to accentuate dimorphic tendencies. On the other hand, it is pretty difficult to tell if something like a hamster is male or female without a detailed inspection. I'm not sure if this topic was ever explored in the Star Trek canon. Did any series in the show's history ever show an alien species where the genders appeared different to an extreme?

The bird shown here is of a species where the males and the females look like a totally different type of bird. Only a female Asian Koel visited the bird feeder today. 

Whereas in much of the bird world, the male is often flashier or more colourful, in this species the females are most dramatic. The Koel, called Koha in Sri Lanka, male looks much like a large blackbird with very red eyes. The males make up for their generic appearance by having a particular call that is common throughout a lot Asia. It has a magnificent windup with a deep increasing frequency. In this country, the sound is often associated with the local New Year in April. However, one can hear it year round.