Scientists are Nerds

So, I'm taking this class on Neuroethology, which is basically the combination of neuroscience and animal behavior. It's really interesting, and I'm quite a fan of the course, which is surprising because I haven't really studied neuroscience before.
Anyway, I have to write a paper for this class, and I'm writing about how female songbirds choose their mates. I'm doing a ton of research, and I just read an abstract that says the following:

The songs are constructed from smaller units called syllables, and special syllables with a more complex structure (sexy syllables) are known to induce females to perform copulation solicitation displays (CSD) as an invitation to mate. By using computer-edited experimental songs, we first show that females discriminate between songs by producing significantly more CSD to those containing sexy syllables. We then sectioned the brains and used in situ hybridization to reveal song nuclei containing androgen receptors. We report positive correlations between the size of HVC and both total CSD response and the amount of discrimination between sexy and nonsexy songs.

(Emphasis mine, From Female canaries that respond and discriminate more between male songs of different quality have a larger song control nucleus (HVC) in the brain by Stefan Leitner and Clive K. Catchpole)
Sexy songs? Nonsexy songs? In FINCHES?
These scientists are nerds.