A journalist and a wildlife advocate have asked federal court to temporarily block the culling and slaughter of up to 900 bison in Yellowstone National Park this month.

Freelance journalist Christopher Ketcham and Stepany Seay with the Buffalo Field Campaign filed a motion for a preliminary injunction to block the culling and slaughter scheduled to begin Feb. 15.

Last week, Ketcham and Seay sued the National Park Service, claiming it and Yellowstone National Park prevent the observation and documentation of park personnel and the captured bison destined for slaughter at a large corral in a remote area south of Gardiner, Mont.

One of their attorneys, Jamie Woolsey of Casper, said that violates free speech protections in the First Amendment.

While their concerns probably will be argued in the courts for months, they want to immediately stop the park from the culling of bison unless they can get reasonable access for their observations.

U.S. District Court Judge Scott Skavdahl will conduct a three-hour hearing at 9 a.m. Friday in Casper about the motion to block the culling.

A park spokeswoman has said the restrictions protect park workers and the public because moving and sorting bison can be dangerous.

But Woolsey and other attorneys supported by the Animal Legal Defense Fund wrote the safety claims are exaggerated, and park officials routinely allowed access until 2006, with no reports of anyone being injured.

The primary issue, she wrote, centers on free speech rights. "By preventing the public, including Plaintiffs, from viewing the culling activities in Yellowstone National Park, the National Park Service infringes on Plaintiffs' continuing right of access under the First Amendment of the U.S. Constitution."