The photographic equipment consisted of a digital Canon 20D camera with an EF 200 F2.8L lens and an EF 300 F2.8L IS lens.
The mp3 files available for download from this site were generated with lame version 3.97 and 3.98.
Apart from the mobile hides, I also have hides in permanent positions. An example is shown here.
Sometimes, bait was used to attract birds to the vicinity of a hide. For doves and finches, seeds were scattered on the ground. Vultures were lured with sheep intestines.
Species were identified visually, by combining visual and acoustic clues, or by their vocalizations alone.
I found the following books most useful for species identification:
For Passeriformes: "The Birds of South America", by Ridgely and Tudor, vol. 1 (1989), and vol. 2 (1994); later substituted by "Field Guide to the Songbirds of South America" by Ridgely and Tudor 2009; also "Handbook of the Birds of the World", vol. 8 and vol. 9.
For Cerrado birds: the new field guide by Gwynne et al. 2010.
See also References.
Most software used in this project is open source software, gratis and easily available. Digital picture processing was done with the gimp. Acoustic data were processed with the wavesurfer, a free sound editor from the Center for Speech Technology, Stockholm, Sweden, and with lame, sox and praat. Spectrograms were generated with wavesurfer.
The web pages were created and maintained on a linux system (OpenSuSE , Ubuntu), directly in HTML, with vim, bash scripts and perl. I use a mysql database as a register of the bird species. Many thanks to the Open Software community for their excellent systems and programs.