For those who are scientifically minded but not biologists, I highly recommend the Grant's "How and Why Species Multiply" [0]. It's very well written. If you're much more into population dynamics, you could give their book "Ecology and Evolution of Darwin's Finches" [1] a look. It's much more technical, being aimed at maybe upper level undergrads (in evolutionary bio) or so. They have another book, "40 Years of Evolution: Darwin's Finches on Daphne Major Island", but I haven't read that one yet. Guess I should put it on my amazon wishlist!

[0] https://www.amazon.com/How-Why-Species-Multiply-Evolutionary...

[1] https://www.amazon.com/Ecology-Evolution-Darwins-Finches-Pet...