long passion that became his career.

“I am still learning new things,” he said by phone from his home in Concord, Mass. “In the same woods, the same trails, I still learn new things from watching birds. There are constant, never-ending opportunities for learning.”

The author and illustrator of “The Sibley Guide to Birds” and several other books about birding and nature, Sibley will speak at LSU’s Coastal Environment Building Thursday in a free presentation hosted by the Baton Rouge Audubon Society.

“He provided the best guide, roundly believed to be the most comprehensive,” said Jared Wolfe, program chairman for the Baton Rouge Audubon Society. “He is a naturalist that brings an encyclopedic knowledge with him.”

Sibley’s speech will focus on the “psychology of bird identification,” especially the subconscious “shortcuts” that birders use to identify birds they spot in the field. After birding from an early age, Sibley said he began reading research about the limitations of memory, especially studies about eyewitness testimony in court cases that turned out later to be incorrect.

“I just find it very fascinating the way the brain can trick us,” he said.

Out in the field, many bird-watchers trust themselves to identify birds, but they make occasional mistakes.

“It is all about using your eyes and identifying what it is,” Sibley said. “There is a very pervasive feeling that I believe my own eyes or I believe what I saw.”

It isn’t just that birders convince themselves that they see rare birds while in the field, Sibley said. They often focus on certain birds that have been seen in the area or they read about.

“You see what you are sort of pre-programmed to see,” he said. “It doesn’t have to be a desire or a want. It can be a suggestion.”

During his presentation, Sibley will offer some advice to listeners. Of course, the first step is for birders to admit they are fallible.

“It is mainly a question of being aware and being able to step back and re-examine,” he said. “Being conscious of the fact you could be doing it is the first step.”

Growing up the son of a Yale University ornithologist, Sibley began bird-watching as a child. He was surrounded by ornithology — bird experts gathered at his family’s house, and he often hung around the museum where his father worked.

By the time he was 12 or so, he decided he wanted to study birds and paint them, like John James Audubon and other bird guidebook authors. He started studying biology in college but dropped out because he just wanted to focus on birds. Instead he took jobs around the country doing bird counts and any other thing he could do to watch birds professionally.

“I made my own ornithology study and spent years out in the field watching and drawing, getting to know the birds themselves,” he said.

Painting and drawing the birds since he was a child helped him to learn what the feathered creatures looked like and how they functioned. When he began working in earnest on his guidebook, it took him 12 years to complete it, and it was published around the time he turned 40, he said. But in a way he had worked on it since his childhood.

His guidebooks have “set the standard for birding field guides in our time,” a writer from Birding Magazine said in 2007. They feature detailed watercolor illustrations of birds that beginners can match to what they see while out looking for birds, but they also appeal to longtime bird-watchers.

“I started out wanting to include every bit of detail, every bit of information I could fit in, stuff that would satisfy the expert,” he said.

Sibley encourages beginner bird-watchers in Louisiana to go out during the spring, when birds weighing only a few ounces are migrating and flying in from the Gulf of Mexico during a 1,500- to 3,000-mile journey.

“Anybody can see that at any time,” he said. “It’s just an incredible spectacle.”After a lifetime of studying birds, David Allen Sibley, the author and illustrator behind a popular guidebook series on birds, never stops learning from the same creatures he has seen hundreds of times.

Even walking the same trails near his home each day, Sibley does not get tired of bird-watching, a life