Field Judging Rocky Mountain Bighorn Sheep

By Jay Scott, Field Editor
Western Hunter Magazine
Scoring Photos and Estimates by Tim Rushing

Rocky Mountain bighorn sheep can be found in many of the western states including New Mexico, Arizona, Montana, Idaho, Wyoming, Colorado, Washington, and Oregon as well as several provinces in Canada. Judging bighorn sheep is definitely not an easy thing to do and there is certainly a bunch of experience that is necessary to become consistent at field judging these fine animals.

The minimum score for Rocky Mountain bighorn sheep is 180 inches for the Boone and Crockett record book. Typically record book rams have 38-40 inch horns and at least100 inches of mass. Generally, over 50% of the total score is based around the eight mass measurements. The following questions in regards to field judging were posed to two very experienced sheep hunters and our hope is that you will find their answers to be full of wisdom and will help you become better at field judging sheep.


First, let me introduce our two sheep experts: Tim Rushing from Colorado and Greg Koons from Arizona. Both of them have a lifetime of experience when it comes to Rocky Mountain bighorn sheep. Tim Rushing has been an avid sheep hunter and professional guide for 13 years. He has harvested a B&C ram in Colorado and has guided numerous clients to high quality rams. Tim's passion is hunting for big rams and he typically spends the summer months every year scouting the alpine country in various units throughout the Colorado Rockies. Greg Koons is an Arizona native and has been hunting since he was 10 years old. He is the owner of High Desert Outfitters and has been guiding for 24 years, specializing in bighorn sheep. He has harvested his Grand Slam with a Rocky Mountain bighorn from New Mexico scoring 195 2/8 (which was the state record at the time it was harvested). Greg has been responsible for the harvesting of 48 rams in the state of Arizona.
What is the first thing to determine when looking at a ram for the first time?

TR: Shape and depth of curl. Does the ram make you speak words out loud like "wow" or "whoa?" First impressions are usually correct and I base further scrutiny on that first look.

GK: Is it the age class or size of ram that warrants a closer look? If it is a half-curl ram then you do not need to waste any more time looking at him. I am trying to determine if the ram I am looking at has great mass down low in his third quarter circumference area and good length of horn.


How do you determine the mass at the bases?

TR: From a slightly quartering angle, I look for any signs of extra space between the middle of the ears and the horn. Big-based rams show very little space and small-based or average rams will show a lot of space. I have found the space between the horns at the top of the head to be a very poor predictor of base size due to the fact that rams have greatly varying sized skulls. I've seen several big-based rams with a large space between the horns. Base size in Colorado sheep is best judged by studying the harvest statistics by unit. Knowing the historical data by unit will always be one of the best strategies for judging base size. Sure, the odd big-based ram will appear sometimes in a unit that typically produces small-based rams, but they are the exception and not the rule.

This article originally appeared in Western Hunter Magazine and appears courtesy of Western Hunter Magazine. Western Hunter Magazine is your best resource for hunting information for all western species. Whether you are interested in elk, deer, antelope, bighorn sheep or moose we will bring the adventure to your mailbox! Our subtitle is Gear - Tactics - Information - Adventure and we take each of these seriously. We only feature the finest hunting gear available from the finest makers in the world. If you are looking for information or looking to buy, we will steer you in the right direction. In each issue you will learn tips and tactics from the most experienced hunters in the west. With articles on field judging trophies, glassing techniques and calling strategies, we guarantee you will learn something new in every issue, and will continue to become a more knowledgeable and skilled Western Hunter.

GK: I typically research the history of the unit and the rams that have been taken in the area by the record book and the past successful hunters. This list can be obtained from the Game and Fish Department for each unit. It will give you the base circumference, the horn length, and age of each ram that has been harvested in that unit. This will give you an average of bases that are typical of that unit/gene pool. Let's say the data says average rams that have been harvested have 14-1/2 inch bases. I use that when I am guessing a ram and if he is bigger than that then it is just a bonus.


How do you determine the length of horn?

TR: Overall shape:
•Flat out-of-the-head appearance – makes for shorter horns
•High out-of-the head appearance – makes for longer horns
•Squashed or egg-shaped look front-to-back where the horn may curl upward at or just beyond the eye (from a side view) – makes for shorter horns
•Extra wide – makes for longer horns
Depth of drop and circular overall shape on a full curl ram:
•Above jaw line – 30-33" length
•Equal to jaw line – 34-36" length
•Below jaw line – 37-40"+ length