Beautiful site.

Aside from actually being there in the rainforest, perhap using a flash applet with real sound tracks from different times of day and places. If you have access to high-res photos of locations, offering those as desktop images might be of interest.

For the site itself, you don't want to overdo it. But small things which users can *choose* to activate are always interesting - I can't find any example links right now, but have seen a couple of other sites out of Brazil which really captured the vivaciousness of a tropical rainforest.

Michael - lots of good ideas.

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Overall I like it (seemed like it may have taken a little while to load.)

I really like the header.

The font in the middle column seems too compact? A little hard for my old eyes to read.

The thumb images on this page mariri.net/index.php
are pretty, but I don’t think they work in this size.
I don’t know whether they just need to be sharpened or whether pics this size need to be simpler – something that doesn’t dissolve into a blur of greens and browns when small.

It might help if those images were clickable to larger size – but that might distract.

I like the background gradient and the color scheme overall.

Thank you for having an “about” page that actually explains what your site is about (so many don’t; well they have an about page that leaves you scratching your head).

SitePoint is a pretty good resource for getting (and giving) feedback on page design.
www.sitepoint.com/

Hope some of this helps.

Your site is lovely. wish I had a suggestion, but for most part I enjoyed the whole site.