Busy birds in spring reloaded

Busy birds in spring,
up in single file,
twigs in mouth,
gorgeous holes
to build a nest.

In the meanwhile I even learned the name of my busy birds. They are blackbirds (Amsel). Before you send me a shit storm for not even knowing how blackbirds, or merles, look like, I’ll tell you they were female blackbirds, which look pretty different from the very black male blackbirds. That’s what confused me at the beginning.

I must admit I don’t know much about birds, beyond being able to differentiate house sparrows from swallows, or sea birds. A small, mysterious, grey bird with a narrow muzzle, a slightly orange-red tail, and a clattering voice just built a nest in a pretty unlikely place in our balcony. I don’t know if it is male, or female. I also don’t know if birds build nests only for their offspring, or also for themselves, to spend the night.
I searched the web and my bird has a certain similarity with a nightingale. Awesome! I have never consciously seen a nightingale in my life. I have only heard about them in romantic literature. But nightingales are supposed to have a white breast, and they are great singers. My mysterious bird has a grey breast, and sings like shit, at least while I am present.

Well, all of the above, including my slight obsession to name, own, classify, and rate stuff, backs the following ad-hoc hypothesis:
I am a pretty stupid person with a high IQ.

I am starting to learn, though…