This in itself shows team work. They failed to get rid of the owl in time before the breeding season.
Next season they tried again. This time, together they stuffed the nest hole with so much stuff that the owl couldn't get in anymore. The owl would try to clear it but soon gave up as it was two working against one. With the owl permanently gone, they cleared the hole and seized it.
Isn't that stunning? This demonstrates memory as the previously failing tactic was not repeated. The idea of stuffing a nest surely isn't intuition or a skill learned from parents, it's a spontaneously formed idea for a highly specific problem.
They also have very complex social behavior where males exchange favors. Every bird knows of every other bird they commonly interact with whether they are owed or in debt. So that means they have a currency.
We should lose our arrogance and look at wildlife with new eyes and with new respect. And not just for wildlife superstars like crows or dolphins, do it across the board. Case in point, earthworms drag leaves into their underground lair and feed on them. When you give it the wrong type of leaf, it will reject it. When you give it the right type of leaf, yet wrongly oriented, it will turn it around. We're talking about a creature with a handful of neurons, figuratively speaking. It's one of the most stupid life forms and it can do that.