"It works and I know enough to say I could finish it if I want to, so I'm done here. On to the next thing!"
I love how that pigeon looks half head-empty-but-proud, and half "I know, I know" in that last panel.
I may be wrong, but it looks like laying eggs is just like pooping. The is gonna come out no matter if your nest is ready or not. Maybe this pigeon had its nest destroyed and did the best it could to build another one.
Nope. If you look it up there's serveral instances of rock pigeons making "nests" like this, it's legitimately just a thing they do specifically.
It's unfair to call them shitty, rock pigeons make nests on flat, stable surfaces, and are tended to by both parents in shifts, so all the nest needs to do is prevent the egg from rolling away when they get up. The nests are perfectly suited to purpose, it's us humans who are imposing unfair beauty standards for what a nest "should" be.
The nest is either never completed or it is done in half the usual time with perfect symmetry and sub-millimeter accuracy.
There is no in between.