For Shedd Aquarium penguins, love is in the air

Forget the flowers, chocolates or champagne. For these lovebirds, the answer is in the stones.

Some 50 penguins at the John G. Shedd Aquarium kicked off the breeding season with what is, for penguins at least, the most romantic of activities: rock-hunting.

Each year, marine trainers scatter rocks throughout the aquarium's Oceanarium where the birds swim, waddle and eat. The rocks are brought in around the same time that the penguins in the wild would begin mating. The sleek black-and-white birds use golf ball-size stones to build the nests where they will lay their eggs.