Bison_7_mother_and_calf Up until the early 1800s, 30 to 70 million bison roamed free on the open prairie and high plains of North America. By 1900, fewer than 1,000 American bison (Bison bison) remained.

Thanks to the efforts of Native Americans and conservation crusaders, the slaughter of the bison ceased and the population was allowed to grow again. Today more than 65,000 bison graze on the open lands in the U.S. and Canada. Yellowstone National Park, home to more than 3,000 bison, boasts the last remaining American bison herd in the lower 48 states that has been continuously free-ranging since prehistoric times.

Photographing these majestic animals that have a strong and lengthy link to North America's past can be a bit underwhelming. Bison don't really do much during the day other than stand around, eat, chew their cud and wallow in the dirt. But there are a few times of day and year when their activity level changes - even if ever so slightly.

• Early morning or late afternoon: These are the most active times of day for bison - when the air is cooler and the sun is lower in the sky. These times of day may also be great for photographing the breath of the bison because of the difference in temperature between the cold air and the hot breath. The light will also be much better to bring out the detail in the dark coats of the bison.
• July to September: This is when bison are in their rut, or mating, season. Beginning in July, males will search out females in heat. When they find one, they stick to her like glue, a habit called tending. Tending can last for a few minutes to a few days. It is the cow's choice to mate with the male. If the cow is not receptive to the bull's advances, he will move on to another cow. The interaction between the bull and cow can make for interesting subjects. The males may also fight over females they are tending. These battles, when horns clash and dirt gets kicked up, provide excellent action shots.
• Dead of winter: In places like Yellowstone National Park, where the bison have learned that the thermals provide warmth during the cold winter, the ice will freeze on the coats of the bison. These iconic shots of white ice on dark fur demonstrate just how thick the bison coats are because the ice doesn't melt.
• Late April to June: Bison calves are born in late spring after a nine month gestation period. When born, these little bundles of joy have reddish coats and can walk just a few hours after birth. Witnessing - and photographing - wobbly newborns with their big, black eyes and fuzzy, red coats makes for a special moment.

The biggest challenge to photographing bison can be their dark coats. To avoid the contrasty photograph, take pictures of bison in early morning or late afternoon sun or on a cloudy day. When possible keep the angle of the sun behind you so the face lights up and the catchlight of the sun shows in the animal's eyes. Side lighting on a sunny day may produce harsh shadows, but done properly, can create interesting tones in the photo. Back lighting may blow out the background but with correct exposure, rim light can be created around the bison to add a nice effect.

Bison can be very unpredictable and dangerous. When photographing them, keep your distance, especially with mothers and calves. Signs of an uncomfortable bison include:

• looking up at you (changing their behavior)
• pawing at the ground
• tail in upright position means either charge or discharge

Places to photograph bison

• Yellowstone National Park, Wyo.
• Grand Teton National Park, Wyo.
• National Bison Range Wildlife Refuge, Moiese, Mont.
• Bison herd overlook near Genesee, Colo.
• Rocky Mountain Arsenal National Wildlife Refuge, Commerce City, Colo.
• Sullys Hill National Wildlife Refuge, Fort Totten, N.D.
• Custer State Park, S.D.
• Fort Niobrara National Wildlife Refuge, Valentine, Neb.
• Neal Smith National Wildlife Refuge, Prairie City, Iowa
• Wichita Mountains National Wildlife Refuge, Indiahoma, Okla.