Punk-chicken
Hoatzin Opisthocomus hoazin – What a strange bird!
Just as I thought I had it figured out and preparing for this post, I decided to check the references on the wikipedia-page. I knew it’s not a Chicken or a Pheasant and probably not a cuckoo. Sceletal studies indicated that the Hoatzin is closest related with the Sereimas Cariamidae, but a DNA study published in 1999 concluded convincingly that the Hoatzin is a Turaco. Made perfect sense when I thought about it. So I believed until a few hours ago. 
Since then, new studies have been carried out using longer strings of DNA and larger samples. And the result now is NONE of the above. Wikipedia indicates that if anything its closest related with Doves! I am in shock! In search of a second opinion I find John Boyd’s excellent site on bird taxonomy – A taxonomy in flux. In Boyd’s taxonomy tree Hoatzin is placed basal in Pelecanae: Waterbirds, Waders, and Cuckoos (and which also include Bustards, Cranes and Turacos)
Conclusion: Hoatzin is a weird bird with no close relatives. What else is new?
I am just confused!
Archeopteryx – Not!
Although, it can be concluded from the taxonomy discussion above that Hoatzin is a very old type of bird – it is not related to Archeopteryx from the Jurassic era. Archeopteryx was a feathered dinosaur with some birdlike features. On the other hand Hoatzin has some interesting features shared with the Archeopteryx. The young has claws on the wings used to climb branches. See this video
The sound it makes is mainly a series of loud hissing – like I imagine the ominous breathing of a dinosaur.
It eats mainly only leaves and has an enlarged crop filled with enzymes and bacteria to digest the fibers, which leaves little space for a flight bone making it a poor flyer.
The complex digestive system gives it a bad smelly breath which has given it the nick-name StinkBird. The Hoatzin is not hunted because also the meat is foul.
Hoatzin is national bird of Guyana.
Lago Lindo
I visited Tarapoto with the family for a couple of days and had the opportunity to visit a fairly new site with an excellent lodge – Lago Lindo, which proved a stronghold for Hoatzin – and good general birding which I will account for elsewhere. In spite of my lens having a focusing problem I manage to get some half decent pictures and both my daughters (1.5 and soon 4 years old), now have a new favorite bird!
