J.D. Irving Ltd. is challenging the constitutionality of Canada's Migratory Birds Convention Act.

Lawyers for the New Brunswick-based company have filed a notice of motion alleging the act is too vague.

The regulations contained in the legislation are meant to protect migratory birds, their eggs and nests.

The move comes in response to wildlife charges laid against Irving in connection with the destruction of great blue heron nests near Cambridge Narrows, about 80 kilometres north of Saint John.

In the summer of 2006, J.D. Irving Ltd. built a new logging road on company-owned land that destroyed an area containing heron nests.

Estimates previously suggested between 12 and 20 nests in the area were destroyed when the wide track was put through the company property.

The company announced that it would be taking steps to avoid further damage, including not harvesting in the area for one year, establishing a 400-metre permanent buffer around the area and decommissioning the road.

The incident sparked a Canadian Wildlife Service investigation.

The company was charged with disrupting a nesting colony under the Migratory Birds Convention Act, to which it has pleaded not guilty.

Court documents now filed by the company say the bird act should be declared unconstitutional. The documents allege the act is unnecessarily broad and lacking in precision.

The act was established in 1916 as part of a treaty between Canada, the United States and Mexico.

"If you tried to be more specific you would make it more difficult to implement the act and to protect birds," said American ornithologist Jeff Wells.

"The treaty that this law was based on was really one of the most forward ways of achieving that kind of conservation. It's been spectacularly successful."

J.D. Irving has not responded to requests for comment from CBC News.