Who said that the birds are not intelligent? It seems that they are very intelligent.
The bird on the picture has more water-filled tubes in which is food, but are too high and too narrow for the bird to be able to reach the food with its beak.
Next to these tubes, there are small objects which she could use to raise the water level so that she can reach the food inside the tubes. Even though no one would have expected her to realize these things, to everyone’s surprise, she really did, she manage each time to reach the food.
Until now, people had no idea that birds have a 7 year old human intelligence.
Even though they can’t talk, that doesn’t mean that birds can’t think and solve problems.