I've always been impressed by birds' abilities to learn quickly.

When I was trapping moths in the mid 80's, I operated my light trap in the garden and after only a few nights of trapping I realised that not all the moths attracted actually end up INSIDE the trap, quite a few were on the outside when I got up early the following morning to log the total catch (which I used to do assiduously). The birds had also cottoned on to this within 3 or 4 days and were already taking those moths which were roosting on or outside the trap ahead of me, necessitating that I needed to be up at the crack of dawn to deny them an easy meal. Not only was I anxious not to miss a good moth, but I also felt some responsibility towards the moths themselves.

Recently, spending much of the summer away and therefore not able to keep on top of gardening chores too easily, the wet weather has meant an explosion of weeds in the garden borders and rockeries here, so much of my available free time is spent weeding. Yesterday, following a relatively dry spell, I put in an hour in the late afternoon. As I turned over the soil, weeding on one of our rockeries, I noticed that I was exposing quite a lot of ants with their larvae.

Sure enough this morning a juv. Green Woodpecker was exploiting this, picking off ants/larvae where I had been working and I got to pondering how it had reacted so quickly.
The answer was quite simple. The juvenile had been here at least 3 times before in recent weeks with an adult male; ( - a couple of weeks ago, I had photographed the latter feeding the juvenile on our lawn within 6 feet of the area where I had disturbed the ants yesterday). I conclude that the juvenile had seen me at work yesterday and considered it worthwhile to check it out this morning, and scored big time.
Aren't birds great!