Mr Lester was a well-known animal advocate who assisted a number of agencies in WA.
The Mandurah local was known to travel to all parts of the state if it meant being able to rescue a sick or endangered bird.
Last October he came to the aid of three birds injured at the popular recreation spot Woodman Point.
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READ NOWWA Sea Bird Rescue, a group Mr Lester helped found, posted a heartfelt tribute to him on Wednesday.
“Craig will be remembered with great love and admiration from many of our active rescuers and supporters,” the post read.
“He was an inspiration.”
Native ARC manager Dean Huxley said the news came as a shock.
“It’s very sad news,” he said. “He was one of kind. He liked doing things his way but he was so good at what he did.
“Everything he did was for the animals.”
In another tribute posted on social media, WA Birds group member Nathan Piesse wrote that Mr Lester was a selfless man who dedicated his life to helping sick and injured birdlife.
“The stories he used to tell me about the things he used to see and hear would blow anyone away,” he said.
Mr Lester was 55.