Cowboys hired by Utah State Parks on Saturday gathered the 700 bison that roam freely on Antelope Island in an annual event observed by hundreds of people.

The drive began at the Fielding Garr Ranch, where the bison were pushed across the island to corrals near White Rock Bay.

Later this week, the animals will receive a health screening and treatment as necessary. Most will be returned to roam the 16-mile-long island, while many will be auctioned to reduce the herd size to 550.