A Beast the Color of Winter in my mind; probably because I read them during the same period in my life and they are of similar quality (although the animal subjects could not be more different!).
There's an entire article about the red-spot aspect of the study here. I guess there's a reason that part of the book stood out to me! Also an interesting tidbit here from a current worker in the field who reflects on Tinbergen's words.
Rating: 4/5 255 pages, 1953