Cowboy David Thompson talks on the telephone while eating dinner at the end of the day during a week-long operation to gather cattle, near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson drinks a cup of coffee before leaving for a day of working to gather cattle near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson walks with his dog, Fang, to catch horses that he will use for a day of gathering cattle near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson puts a horseshoe on a horse's hoof as he prepares for a week of gathering cattle near Ignacio, Colorado June 9, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson gestures as he loads his horse into a trailer near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Rancher Steve Pargin holds a young border collie that cowboy David Thompson had brought to him while they prepare to gather cattle near Ignacio, Colorado June 10, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson carries the reigns of a horse's headstall while preparing to gather cattle near Ignacio, Colorado June 10, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson drives his truck to join with a group of other cowboys to gather cattle near Ignacio, Colorado June 10, 2014. REUTERS/Lucas Jackson 

A rodeo champion buckle adorns the belt of cowboy Stetson Mackey as he waits to begin a day of gathering cattle near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson works to help a horse regain its footing after it fell inside a trailer on the way to gather cattle near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson inspects a cut on a horse's ear after it fell inside a trailer on the way to gather cattle near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboys are pictured past a saddle mount, up on their horses after eating lunch near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

Rancher Steve Pargin and cowboy David Thompson (R) talk with the rest of the crew during a cattle drive near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboys Wyatt Williams (R) and David Thompson work to restrain a calf in order to give it medicine near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson looks down on a large herd of cattle during a week of gathering cattle near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboys Rollo Mangus (L) and David Thompson work to move a large group of calves up a trail during a week-long operation to gather cattle near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

Rancher Laura Pargin holds a warning flag in an attempt to slow traffic as cowboys push a herd of cattle across Highway 160 near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboys push a herd of cattle across Highway 160 near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboys (L-R) Grant Gunn, Jody Mangus, Mead Gonzalez, and Georgie Dittmar push cattle through a gate after pushing them across Highway 160 near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

A horse bucks as it tries to run from a saddle that had become loose during preparations to gather cattle near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson looks back through trees as he rides his horse near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

A cow inspects cowboy David Thompson as he rests on the ground near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

Cowboys Stetson Mackey (L), Wyatt Williams, and David Thompson (R) rest in the shade of a pine tree after lunch near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

Cattle cool down and drink water at a man-made reservoir in the mountains near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson sits with his dog, Amelia, as she cools down after a day of gathering cattle near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson uses a rope and stick as he works dismounted to move a large group of calves up a trail near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

Cowboy Rollo Mangus works to cut mothers and their calves away from the larger herd near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboys Wyatt Williams and David Thompson restrain a calf as Stetson Mackey prepares to give it medicine near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboys David Thompson and Wyatt Williams release a calf after giving it medicine near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson separates cattle from each other in a pen near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson separates cattle from each other in a pen near Ignacio, Colorado June 12, 2014. The land where the cattle graze is leased from the Forest Service by third-generation rancher Steve Pargin. Several times a year, he and a crew led by his head cowboy, David Thompson, spend a week or more herding cattle from mountain range to mountain range to prevent them from causing damage to fragile ecosystems by staying in a single area too long.



REUTERS/Lucas Jackson 

Cowboys David Thompson (L) and Wyatt Williams tease Grant Gunn as he climbs over a fence near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboys (L-R) David Thompson, Grant Gunn, and Mead Gonzalez compare notes with rancher Steve Pargin (R) near Ignacio, Colorado June 12, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson stands with a horse that he will use for a day of gathering cattle near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson removes burrs from his dog Fang that had become stuck to her fur while helping to gather cattle near Ignacio, Colorado June 10, 2014. REUTERS/Lucas Jackson 

Cowboy David Thompson prepares dinner for himself near Ignacio, Colorado June 11, 2014. REUTERS/Lucas Jackson