Dummy eggs are manufactured for domestic birds. Left alone, female birds will continually lay eggs; if the eggs are destroyed, they'll just lay more. Rather than constantly destroying eggs or ending up with lots of unwanted chicks, owners can replace the eggs with dummies immediately after they're layed-- the female will then incubate the dummy eggs indefinitely rather than laying new ones. Luckily for me, goose eggs (77x50 mm) have approximately the same dimensions as pelican eggs (70x45 mm).
While trapping pelicans on nests, we'll replace the viable eggs with dummies to prevent egg damage. This allows us to store the eggs from the nest in a safe place during capture and return them to the nest intact once the bird is in hand. In total, this usually means only about a 15-20 minute gap in incubation. If all goes according to plan, the pelicans won't notice the difference!