Charlie24601

Its a confusing topic to understand, or even explain sometimes. Here's how I understand it:

Any creature understands the concept of nothing. When all the meat is gone from a gazelle, the predators and scavengers leave because there is zero meat left.

However, what we didn't really understand until recently was that zero doesn't just mean nothing, but that zero HAS A VALUE.

Only the most adorable and amusing test ever done: https://www.youtube.com/watch?v=QX_oy9614HQ

Zero is an actual number. It is not the absence of a number.

Would you happen to have any links or publications we could look at? This sounds fascinating, and I'd love to read more.

Not really her area of expertise, but I'll give you an answer: Small birds flock in large numbers. When they are making lots of noise they are essentially communicating which lets them feel that everything is ok.

They stopped because one of them spotted something unknown or dangerous and the rest stopped what they were doing to pay attention. They then decided the object of concern was too close or too dangerous, so they evacuated the area.