I've just finished paraphrasing and proofreading the classic 1893 book "Parables from Nature" by Margaret Gatty. This is a living book that Charlotte Mason used with her own elementary-aged students.
It's got 29 (I think? I didn't count them) stories that illustrate a spiritual truth via a story involving nature. In other words, it's more about moral truth than about nature. There's a story about dragonfly nymphs who can't imagine any world other than the world under the pond where they live, a horse who refuses to submit to authority, a garden of plants who yearn to be wild and free to grow however they want, a tree who says, "I gotta be me!" even at the expense of his neighbors, etc.
The language can be challenging if you're not used to flowery Victorian writing, so I paraphrased it for Ambleside Online students, but it's free for anybody to read online:
http://www.amblesideonline.org/ParablesParaphrase.shtml
Many of the stories are easily grasped by kids, but a couple of them are more relevant for adults. The very last one, Birds in the Nest, is a good one for moms to read when they're missing the days when their babies were little. The Deliverer is good for Christmas, and A Lesson of Hope might go over children's heads but would probably help someone struggling with sadness.
Inferior Animals is funny - a bird tries to explain where people came from; it's sort of a twist on evolution.