Bird Intelligence

There is this bird couple at my house and I can not decide if they are really stupid, super smart or just plain lucky. I have hanging baskets of flowers that hang from the covered area of the walkway to my front door. Every year I fill them with flowers, attempt to remember to water them and hope they look as good in real life as I hoped when the project began. The last two years this bird couple has built a nest and raised a family in one of the baskets. Since they are high up, the first year I didn't know this until the babies started making noise. I had been watering not only the flowers, but the nest, the eggs and the babies! Year two I knew what was going on and was more careful, but something scared them away from the nest when the babies were just hatched and so no baby birds :(.
To this year-I got lazy and decided I wanted the baskets to look good and less stress so when Michael's placed their silk baskets on sale, I bought some. I have beautiful flowers and if someone has a problem with them being fake, turn around and walk away from my door. The birds are back. I thought for certain the would pick another place for their nest after last year. Nope! And, they are better off than ever because I won't water them and there is this great fake moss stuff in place to start the nest building.
So what do you think, stupid, smart or lucky? My vote is a little of all three!