I took a pass at flocking.
Unfortunately, i've lost the source-code to this app. Jeeze!

But the download is still fun to play with.
The essence of flocking turned out to be collision prediction.
With the simple rule of just avoiding Predicted Collisions, birds tend to align in self-organizing flocks!
Other rules were added for Hunting, and dealing with walls has some problems, but basically it was fairly simple.

Here's the download and a few screenshots.
Hello from 2022.
Windows currently informs me this ancient executable of mine contains malware.
Download at your own risk!
The URL is "Flock1.exe" in the current folder.

collision predictions

Everybody's chasing the white one.
Every bird has a fixed speed, and about half the chasers
are faster than the chasee. so amusing!

more chasing

The faster birds in front are trying to curve around
to get at the slower target behind them.