The bison were removed from Great Bend’s Brit Spaugh Zoo on Tuesday, and shipped to a 30,000-acre preserve in Nebraska.

Zoo Director Scott Gregory, wearing an orange vest with the word "shooter" and standing ready with a shotgun, watched zoo staff herd the animals into a livestock trailer Tuesday morning, before the zoo opened to the public. He said the male and female, along with their 6-month-old calf, were being removed for safety reasons.

"They’re too dangerous for this enclosure," Gregory said. The male has been charging the safety fence, threatening to knock it down. Meanwhile, the protective mother bison has been charging at zookeepers when they enter to clean the area or feed the animals.

The adult bison, also known as American buffalo, are eight or nine years old and weigh about 1,500 pounds, Gregory said. They have been a popular exhibit at the zoo for a few years now, but they are becoming more aggressive.

The female, known to zoo staff as "Buffy," gave birth to "Burt" on Dec. 14, 2010. It was her second successful pregnancy, and she also had two miscarriages in recent years. The zoo wasn’t planning on expanding its herd, so the last calf went to the Sedgwick County Zoo.

"We have to renovate this entire enclosure," Gregory said after the bison were removed. Eventually, with approval from the City, something else will take their place. It may be bison, or it could be some other animal Gregory has in mind.

A lot of people enjoyed coming to the zoo to see the buffalo, the director said. "The animal we replace them with has to be pretty impressive."