40 baby bison expected this spring at Rocky Mountain Arsenal

Driving the news: At least six calves have been born so far this month at the 15,000-acre park in Commerce City, Sarah Metzer, the refuge's visitor center manager, tells Axios Denver.

• Roughly 40 new bison babies are expected this spring, Metzer says.

The big picture: Spring is prime time for wildlife enthusiasts to visit the park. Migrating birds return, prairie dogs pop up, and animals like deer and coyotes can be spotted more frequently.

The intrigue: Burrowing owls are another big draw this season.

• And a black-footed ferret has been making an appearance on the wildlife drive during the daytime, which Metzer described as "really amazing" to see.

Pro tip: With bison at the refuge roaming freely — making sightings a matter of luck and patience — Metzer suggests stopping by the visitor center for the latest information on the herd's location.

• Bringing binoculars is a good idea, too.

If you go: The refuge (6550 Gateway Road) is free to enter and open daily from sunrise to 8pm. No pups, except service dogs, allowed.

• Bison herds are very protective of their young, so be sure to respect the refuge's rules and admire the shaggy newborns from the safety of your car.