So, I'm guessing we've all been there, we've fed and played with all our lions, thinking we've done everything just right... then on your next RO you remember: You forgot to nest! Well, since we already have a counter saying X lions are about to leave, I thought, why not add a banner saying: "This territory has X unnested lionesses giving birth tomorrow, their cubs will be in danger" and it only disappears once you've nested them, much like with feeding/playing. It could be on your den page. Yes I know it's mentioned in the Daily RO summary but I for one still forget, so I think it needs to be more visible.

Lil Bean suggested a toggle on/off button. I agree.
2024 Edit: This has, recently, been added on Wolvden, so I don't see why it shouldn't exist here as well. It is exactly what I suggested.