Grizzwold by Syd Hoff is one of mother's early reader books. I don't know if she had a thing for stories about bears or they were just incredibly popular when she was a child. Anyway, she had a bunch of them.
Grizzwold is a bear — perhaps a grizzly bear — who is feeling the crunch of the shrinking environment. He, like so many bears (think of the hot tubbing bears near the Angeles National Forest), decides to find a new home, in and amongst the human beings who have displaced him.
Grizzwold ends up in all the places displaced bears go — inside the home (as a living bearskin rug!), the circus, the zoo, but none of these places provide the safety and happiness he so desires. Fortunately there is a home, one very much like the one he was forced out of, but this one is protected — a National Park.
It's a fairly typical pro-environmental story but Hoff brings just the right amount of humor and sensitivity to it. Usually the bear isn't made the protagonist, even when he's the one being displaced.