Do squirrels tell other squirrels that there is food?

Honestly, I'm not COMPLETELY sure, but I once saw two squirrels in my backyard. One was halfway up a fir tree while the other was searching for food at the roots of a second fir , I supposed. A pale tabby cat leaped at the grounded one but the squirrel climbed the other tree. There was two squirrels in the trees and another came by while the cat hid in some bushes at the edge of our yard. The squirrels in the trees started making duck-like high-pitched sounds as if they were warning the third squirrel about the cat. The cat jumped out and the third squirrel climbed our neighbor's fence and scurried away. (The tabby wasn't ours)

So I do think they occasionally communicate.