California's Bighorn Sheep: taking some heat for an accurate census

When you think of bighorn sheep, what image comes to mind? Nimble rock climbers? Mountain-bound and well-adapted to their environment? And so, if you felt compelled to count them, you would grab your best insulated sleeping bag, parka, and warm boots and head up the slopes, right?

Well, not so in California. In the mountain ranges of southwest California, the bighorn sheep is endangered as their populations have been threatened by habitat fragmentation, diseases from feral cattle, and predation by mountain lions. But to effectively monitor their numbers on an annual basis, the Anza-Borrego Desert State Park rangers, assisted by volunteers from The Nature Conservancy, position themselves in the blistering summer heat of the low desert to await their quarry.

Why? Because this time of year, the bighorn sheep will come down from the mountains to drink at the small watering holes along the desert's edge. That's easier for the researchers than hiking in difficult terrain. Easier, if you like 108 to 115 degrees Fahrenheit.

“This state park’s bighorn census is the most accurate feedback on how effective the recovery efforts are for the endangered bighorn sheep,” says Dave Van Cleve, the Nature Conservancy’s senior project manager for the region. “It’s a brutal job, counting sheep in this blistering heat, but it’s the most reliable method available.”

Fortunately, the news has been good. The number of bighorn sheep have been steadily increasing for the past 40 years (last year 354 sheep were counted). The census numbers provide state park management with the information to gauge the effectiveness of their conservation efforts - like removing all cattle from the park and prohibiting off-road vehicles from palm and riparian oases that provide food and shelter for the sheep.

Congrats to the Nature Conservancy for their support with the challenging annual desert census. According to the group, "The [Nature] Conservancy is actively working to weave conservation lands into a connected network for wildlife like the bighorn sheep, mountain lions and other species that need large habitats. Recently the Conservancy helped the park acquire more than 4,000 additional acres of prime bighorn sheep territory and worked with California’s Fish and Game Department to acquire 7,400 acres adjacent to the park — key habitats that will contribute to a broader corridor for the park’s large mammals."

Have a cold one on me, folks. You deserve it.

Read the article in The Nature Conservancy website.