For example this:
www.mammalwatching.com
It only gets interesting quite late in the comments, when Carlos Bocos joins in...
This one of quite a lot of cases where a "Holy Grail" species is claimed by him, but no proof is provided. Just last week he claimed to have seen Helmeted Guineafowl ssp. sabyi (or at least some of their ancestors). Given that they are believed to be extinct a little documentation would have been great and surely it's not too hard to get a picture of such a conspicuous bird, right?
Anyways, this thread is about Zapata Rail. I doubt that a random birder will have mich success in the few days they can spare around Zapata swamp. A scientific expedition on the other hand should be able to gather the necessary resources and develop a methodology with high success chances, shouldn't it?