...and what to they call it?
Flipping nidification, that's what.
Nidification is nest building. It's the marvellous instincts and careful labour that produces one of these:
Nesting colony of Montezuma Oropendolas
The Purple-crowned Fairy makes its nest with spider silk.
Mind you, just occasionally, as in the case of the common kingfisher where the only lining of the nest consists of droppings and smelly fish remains, perhaps nidification is fair enough.
Mostly, though, to nidify...urgh. I mean, there's no reason why scientists shouldn't have souls.
Word To Use Today: nidify. This word comes from the Latin nīdus, nest, plus facere, to make.
But that's no excuse. you know.