Mama robin is in a new position in her nest every time I visit; I seldom see her off the nest.
Here’s some information about nest sites from the Cornell Lab of Ornithology:
“Female robins choose the nest sites, which are typically on one or several horizontal branches hidden in or just below a layer of dense leaves. Nests are typically in the lower half of a tree, although they can be built as high as the treetop. American Robins also nest in gutters, eaves, on outdoor light fixtures, and other structures. In western prairies, American Robins may build their nests on the ground or in thickets, while in Alaska they sometimes nest on buildings or cliffs.”