the effects of a sky without stars

[Irbis]

I imagine nights would be far, far darker without any light source whatsoever (at least on nights when there is no moon). I wonder if one night out of every month of total darkness would affect things in the long and short term. In the long term, would it affect evolution and favor nocturnal species?
In fact, can anyone answer just how dark such nights would be?

After quick research - Venus, Jupiter and Mars are all bright enough to cast observable shadows. You'd need for all of them to be on opposite of Earth to have truly dark night, something quite rare, I'd imagine. Classical planets would be seven worlds, not six, as Uranus would be easily spotted if not for stars.

If we assume there is only Sun and Moon, even new Moon at its darkest is still about as bright as Jupiter/Mars are, and 4 times as bright as brightest star. So, truly dark nights would be rare, I'd imagine. All that really changes is that migrating species probably evolve to use magnetic, not celestial orientation, I'd guess?

[Broomstick]

since we already have migrating species that seems to use magnetism that's quite realistic.

[Ziggy Stardust]

All that really changes is that migrating species probably evolve to use magnetic, not celestial orientation, I'd guess?

To be fair, in real life most migrating species already DO use magnetic cues. Outside of the sun and the moon, there is scant evidence of animals navigating by the stars. In fact, so far as I know the only animals that have shown any capability of moving themselves with relation to the stars are dung beetles and warblers.

[Ziggy Stardust]

Sorry for the double post, but the mention of animal navigation got me thinking.

How would the lack of stars affect the patterns of polarized light in the atmosphere? Although most of that light comes from the sun and the moon, is it possible that the disappearance of the stars to have a noticeable effect? Many insects navigate by being able to detect and analyze these patterns (honey bees being the best example). In fact, there are some who claim that the famous Viking "sunstone" allowed them to navigate by reading these patterns, allowing them to locate the precise position of the sun even in bad weather.