Achieving just over 5,000 illustrations Achieving just over 5,000 illustrations
Today, all these drawings are gathered in the Guide of field of the birds of Colombia, that the foundation Proaves launched in 2010 in its first version in Spanish, 2nd Edition 2014 in English and in which also worked the investigators Thomas Donegan and Alonso Quevedo.

In 2018, thanks to an alliance with the publishers of Rey Naranjo and with the support of donors in an Indiegogo campaign, McMullan has an updated and renewed version of the book. McMullan wants it to be a book for everyone: easily accessible, written in understandable language and published in a key historical moment for birdwatching in Colombia

With 5,000 color illustrations of McMullan, both of the male and female variety of birds found in Colombia, it is by far one of the most accessible books on the market and easy for professionals and amateurs to take in the field, responding to a popularization of bird watching.
McMullan paints the birds that can be seen in this field guide with watercolors.

He can trace the figure of a bird and its physical details in less than 40 minutes. It is said to be easy, but it is a work that requires effort and knowledge, because it is not the same to paint a male as a female, or a woodpecker, which can be seen in many regions of the country and which may have variations almost imperceptible to the common, But transcendental for an investigator. Nor is it a matter for children to shape the body and colors of hummingbirds, according to him, the most difficult to finish by the tonalities of their feathers and because those colors change depending on the intensity of light.

Why drawings and not photos? Why drawings and not photos?
The answer is both long and wide, but it is justified on two basic issues: the first, in which there are no complete photographic compendiums and having one hundred percent reliable images of all the birds of the country..
And much less, a file in which they can be seen in the same position to make comparisons.
That's why "illustrations remain key to exploratory studies around the world, even the most renowned scientists are still using them as a reference, despite technological advances.".