The surprising part is how the birds weren't frightened away by the disruption. Maybe the imprint of a nest there was strong enough.

Adding some additional context here:

Original Story

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From Argentina

Cordoba: the original way to preserve woodpecker nests by changing lamp posts

The initiative was carried out by the electric cooperative of Ucacha, a small town that is located 250 kilometers from the provincial capital

December 3, 2021

The image, which went viral in recent days, seems to be something of a joke, however, it is real and served to preserve the home of families of woodpeckers who lived on lampposts, which were replaced by concrete ones.

The growth of the quiet town of Ucacha, a small town in the department of Juárez Celman, which is located 250 kilometers from the capital of Córdoba, led to the need to expand the electricity network and, for this, it was necessary to replace the old light poles that were made of wood.

However, when the workers of the Ucacha Limitada Electric and Public Services Cooperative (Cespu) began the task last year, they noticed the nests of woodpeckers in a part of San Martín Square, in the cooperative neighborhood on Modesto Giuliani Street.

As explained to the local radio, FM Vox Ucacha, the manager of Cespu, Gustavo Bernardi, what the men who were carrying out the replacement of the posts were instructed to do is to cut the part where the nests were and place them attached to the new concrete pole that replaced the old one. They even had to respect the height and orientation of the two nests.

The experiment was carried out without knowing if it would work or if the woodpeckers would migrate in the face of the change.

The result, almost a year after the intervention and the changes in the flow of people and homes in the area, left the woodpecker family in one of the two nests. In the other, according to the local media, it is more difficult to observe the movement of birds.

In dialogue with local radio, Darío Chíngolo, who was in charge of cutting the nests and then tying them to the concrete post, said that the nests are quite deep. In addition, he said that he does not know if it responds to the characteristics of these or to the fact that this species continues to enlarge the space with its beak by its own nature.

Some more pics at the linked article.

The US and Canada signed the Migratory Bird Treaty in 1918 to protect birds, nests, and eggs and it is against the law to disturb, remove, or kill them for the most part. Mexico signed a similar agreement with the US in 1936.

While probably very upset, the bird parents likely just watched from a safe distance. When they went back to check, they found the nest, saw everything was otherwise as it was, and carried on. Bird parents, especially bird moms, usually do not stray far from the nest and will do their very best to protect it.

That's very considerate of them. I wish that was the norm everywhere.