Grackles sometimes do the same in osprey nests. Great blue herons are platform builders and generally nest in colonies. The male brings the sticks to the female and she arranges them on the nest, usually in the highest part of the tree. Mourning doves also build platform nests, sometimes on top of abandoned robin nests. Mourning dove nests are often insubstantial, and the eggs in them may be visible from below.
Woodpeckers meet the nesting challenge by gouging cavities in the trunks of dead trees.
Commonly, that's the extent of the nest, though they may soften it with wood chips in the bottom. The entrance to the pileated woodpecker's nest usually faces south or east. For the downy woodpecker, it seems important that the entrance be on the underside of a limb. Wrens, chickadees, titmice and many owls also are cavity nesters. They line the nest cavity with soft grasses, feathers or fur.