Custer State Park’s first bison calf of 2010 was spotted on March 30! Chad Kremer, Buffalo Herd Manager for the park, emailed me this great photo of the little female newborn and proud, protective Momma.

And then yesterday, April 7, Kremer discovered the second calf of the season in the park. He told me that it is typical to see the first calf of the year right around April first, give or take a week. So, these first two calves of the year are right on schedule compared to years-past.

Kremer went on to say that even though a handful of bison calves will be born in the early part of April, the majority of them don’t begin to arrive until the last week of April. Late April through about the third week in May is when the bulk of the Custer State Park cows will have their calves.

Kremer said there are 426 bison cows in the herd that are of calving age and park staff usually plans  for about 90% of them to produce calves. That’s an expected 383 new little ones expected for the park this spring!

They plan for only one calf per cow since it’s not common for bison to have twins. “In my 18 years of raising buffalo, I’ve only seen five sets of twins,” Kremer said. “It’s actually unfortunate when it does happen because the cow will typically only claim one of them.”

When they are born, most bison calves weigh about 40 to 50 pounds and have the light reddish-brown hair like this one. After about three months or so, the calves’ hair will start to change to the darker brown color.

As cute as the little bison calves are, and with the busy visitor season just around the corner for Custer State Park, photo opportunities can be tempting. But, Kremer reminded, bison are wild animals and can be especially defensive when they are trying to protect a baby.

As the Buffalo Herd Manager for the park, few people know bison behavior better than Kremer. “Visitors may find a bison calf off by itself, but please don’t approach them for any reason. The mother usually knows where the calf is and will come back for it,” said Kremer.

So, if you have the opportunity in the next month or two, take a drive through Custer State Park – particularly down around the Wildlife Loop area – and keep your eyes peeled for little ones.

If you do happen to see some new bison calves, consider yourself lucky and enjoy the experience – but remember to do it from the safety of your vehicle.