A stork's nest is built from sticks, twigs and bits of straw, and storks come back to the same nest year after year. Each year they add more sticks. Some nests are over 100 years old and weigh hundreds of kilograms. They have to be very strong to hold them up.
Storks fly an amazing distance every year. In autumn, many Portuguese storks fly all the way south to Africa, where it is warm. Then in spring, they come back to exactly the same nest in Portugal. They use the sun and landmarks to find their way - across thousands of kilometres.
Storks don't really sing. Instead, they 'clatter' - they tip their head back and clap their long beak together very fast, making a sound like castanets. They use this clatter to say hello to their partner when they meet at the nest after months apart.
Storks are part of stories all over Europe. In Portugal and many other countries, people say storks bring good luck. A nest on your chimney is a happy sign, and people leave them alone. In small Portuguese villages, you can sometimes see a stork peeking out of a nest on the church tower, watching everything below.