Thanks to Melinda we know the bird is a Rufous Hornero, native to South America. The nest, or "oven," is constructed by the male-female team. It can take from 5 days to several months to complete.
This always gets me:
"The species is monogamous and the pair bond is long term, sometimes for life."That's true for the Northern Cardinals, 2 of which live in the bushes behind my house - Chuck and Charlene II. I suspect Charlene the First failed to outfly the visiting falcon.