I am writing a fantasy novel centered on an Earth-like planet with icy rings like Saturn. This question deals with certain effects of having such a ring system. Assume the planet is Earth, the rings are Saturn's rings (minus the C and D rings), and Saturn's ratio of planet/ring holds true for my planet.
On an Earth-like planet with rings, there would be a 'ring-shadow' constantly being cast somewhere on the planet. This shadow would only dissipate during the fall and spring equinoxes, at which point it would be centered on the equator, but be so thin as to not be noticeable. From the equinoxes to the solstices, the shadow would increase in width, and slowly travel towards the pole of whichever hemishere was experiencing winter. Further description of the ring-behavior can be found here, with pictures.
I don't think this shadow would fully block sunlight, but it would most likely resemble a total solar eclipse on steroids. Since no sunlight can get around the edges of the moon (because the 'moon' in this case is a ring completely covering the sun), light would necessarily be lower, though likely not at the level of night-time.
This question deals with the effects of such ring-shadows on the local fauna. This is a fantasy novel, but assume there are no creatures besides what we already have here on Earth. I've looked at several articles on how animals react to eclipses, but they all have the same issue: the eclipse is temporary, and very out of the ordinary. The animals aren't used to it.
On a planet with a ring system, they would be used to it, as unless they live at the poles, the shadow would cross them at some point twice every year. How would fauna react to this?
I realize any answer is going to draw heavily on speculation, but I want to make it clear that this question is NOT primarily opinion-based. Any theories or conjectures you come up with MUST be supported by evidence-backed logic, or at the very least have a clear logical deduction trail which can be traced back to observable fact. The best answer will be the one which details the most behavior changes/differences AND is the best backed/referenced by fact.