15 or 20 years ago, CA bighorn was a fairly easy draw and they had lots of tags. Some units had 1 in 2 or 3 odds. Then a disease wiped out a bunch of them. They dropped the Owyhee county tags from about 60 to 15 and they've never increased them.
I've never figured out if there's a real difference between the CA and Rocky Mtn versions. I suspect the only difference is which side of the Snake River they live on. I've searched for CA bighorns online and found nothing. They call it a subspecies of the Rocky Mtn but I can't find any difference other than location.
From everything I have been able to gather, they're just a desert variety of Rocky Mountain bighorn sheep. While it can get pretty damn cold in the high desert country, I think Bergmann's rule comes into play...since Cali bighorns are a touch bit smaller than the true Rocky Mountain bighorns that I have been around.
