Nesting has begun at a Chicago aquarium as penguins gather materials to build a nest.

The colony at Shedd Aquarium consists of Magellanic and rockhopper penguins, who will use lavender sprigs, fig branches, grape vines and pebbles to make nests through to May.

The building is closed to the public but people can use a virtual reality experience to see the penguins.

Animal care teams are still onsite prepping food and will deliver it sometimes while penguins remain in their nests, the aquarium said in a statement.

Caretakers also continue observing the birds through video cameras.

Not every egg laid is fertile, but last year's season produced two new additions to the colony named Calista and Carmen.