(Image source: ostrich270)
A bird built a nest in the mouth of a wolf statue on the campus of North Carolina State University. Someone at the school caught a photo of a baby bird opening its mouth like the wolf does! Mother birds look for a nesting spot that is accessible yet hidden from predators, the right size, and at least somewhat sheltered from the weather. They pay no mind as to whether that place is inconvenient for humans, but we tend to put up with it, because we know how hard it is to make a good place to raise our babies. The requirements for a good nesting place vary somewhat by species.
(Image source: OrangeCosmos)
A Canada goose spotted a large but empty planter at a hospital and decided that's where she would become Mother Goose. The maintenance department thoughtfully rigged up an umbrella for her and a water supply nearby. Yes, there is something about a bird building a nest that makes us all go verklempt and wish the growing family all the best. I've had many a hanging planter dry up without watering because a bird was raising a family in it. Bored Panda put together a collection of birds building nests in odd human spaces like boots, automobiles, signs, and various equipment that you're sure to enjoy.