What's the etymology and significance of yuenyeung (鴛鴦)? 鴛鴦 is a mix of tea and coffee commonly had in Hong Kong (amongst other south-asian countries).

I was wondering about how this drink came into being? Where does the title come from (especially the common radical at the bottom part of the character). What's the reasoning of the name behind the title? 

I could simply search this up on Wikipedia but I wanted to hear your opinions. I don't really trust Wikipedia as a reliable source of information.
鴛鴦 is actually the name of a bird; more specifically, the mandarin duck. 

Here's an image:  


(Look at how cute they are!)  

In Chinese culture, the mandarin duck is a symbol of lovers, much like the lovebird in English culture. The term 鸳鸯 is often used to describe pairs of things that make a good match. As for your drink, this most likely refers to the tea and coffee, which, despite tasting very different (much like the colour difference between the male and female duck), are actually perfect for each other.

The common radical, 鳥, means "bird". "鴛" refers to the male duck, and "鴦" refers to the female.