One of the things I did in my journal was list questions, and the stork question was "are storks considered to be good luck?". It is obvious they are are not likely good for masonry and the size of the nests could easily collapse an old roof, yet they are tolerated. Although I did see a few platforms constructed to keep them off the heritage masonry, like in the upper sketch. Perhaps it isn't good luck, so much as a superstition that destroying a nest would bring bad luck.
I did learn that what we saw were White Storks and that their population has been rebuilding after years of decline due to pesticides. Despite that, one web site cited the number of storks in Spain at only 3,000, so we were fortunate to see the ones that we did. As for good luck, apparently storks are referred to as good luck in many Spanish proverbs, but I did not see a direct explanation as to why the nests were not pulled down. That author also described them as charismatic, which aligns with the affinity I developed for them and their young.