Approximately 350 horses are driven through the town of Three Forks, Montana, during Montana Horses' spring drive, April 23, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Cowboys and wranglers enjoy the fire in camp the night before they drive approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 22, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Approximately 350 horses cross a creek as they are gathered during Montana Horses' spring drive outside Three Forks, Montana, April 22, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Cowboy Leroy Miller holds his belt buckle before driving approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 23, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Wranglers work to control approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 23, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Wranglers enjoy the campfire and visit after gathering approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 22, 2011. REUTERS/Jim Urquhart (UNITED STATES)

A group of horses makes the final run with approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 24, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Wrangler Margaret Whitehead carries her saddle after driving approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 24, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Horses run as they are gathered with approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 22, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Wrangler Don Pugh sleeps by the fire after gathering approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 22, 2011. REUTERS/Jim Urquhart (UNITED STATES)

An aerial view of approximately 350 horses being driven during Montana Horses' spring drive outside Three Forks, Montana, April 24, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Austin Freer plays the violin in camp after the wranglers gathered approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 22, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Approximately 350 horses are gathered during Montana Horses' spring drive outside Three Forks, Montana, April 23, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Sheila Roebuck, a wrangler, watches as a horse reacts after she gave it cookies be gathering approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 22, 2011. REUTERS/Jim Urquhart (UNITED STATES)

A herd of horses runs as they are gathered with approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 22, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Gene White, left, and her husband Mark White ready horses to drive approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 23, 2011. REUTERS/Jim Urquhart (UNITED STATES)

A wrangler works to control approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 23, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Approximately 350 horses are gathered during Montana Horses' spring drive outside Three Forks, Montana, April 22, 2011. REUTERS/Jim Urquhart (UNITED STATES)

Wrangler Nate Cummins rest after driving approximately 350 horses during Montana Horses' spring drive outside Three Forks, Montana, April 24, 2011. REUTERS/Jim Urquhart (UNITED STATES)