Hoatzin sources

Photo 1: http://www.natgeocreative.com/photography/1229646
Photo 2: http://www.factzoo.com/birds/hoatzin-funky-stinkbird-nice-crest.html

Info:
i. http://www.sciencemag.org/content/245/4923/1236.short
ii. http://www.jstor.org/stable/4088763
iii. http://www.creationinthecrossfire.org/Articles/VestigialOrgans/VestigialOrgans.pdf

"manure-like" - http://www.damninteresting.com/the-stinkbird-enigma/
"eye-wateringly horrible" -- field study from my friend Micheal. He collected samples of their feces and regurgitated food while recording the audio of his findings for his work in Northern Brazil. The full quote is as follows "They're smelly. [sound of rustling as he works to pull out a swab] Shit, yeah, really smelly. Like, this is eye-wateringly horrible, oh my god." Afterwards, he got to know what fresh fermented nastiness smelled like, and that spurred him to vomit (?), gag a few times, and then came the "oh fucking christ and lord almighty end me now" comment. I cleaned it up a bit to keep the profanity out, hope you don't mind!