A group opposed to development at the site of a great blue heron nest colony is going to court to halt the project.

The nonprofit group Save the Rookery filed an appeal with the Minnesota Court of Appeals of the Rochester Township Board’s decision to not provide an Environmental Impact Statement of the proposed Pavilion Estates development.

The development would call for cutting down more than half of the trees containing more than three dozen great blue heron nests.

RELATED: How long have the herons been on the hilltop?

Environmental experts say the nest colony, known as a rookery, is unique because it’s located in an upland forest and not in a low-lying area near a major body of water.

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The township board accepted an Environmental Assessment Worksheet of the site Sept. 9. The EAW was conducted to find if there would be significant wildlife impacts from the project and whether a more detailed investigation into those impacts should be outlined in an EIS.

Under Minnesota law, advocates for doing the study can appeal that to the Minnesota Court of Appeals.

In the filing, the group argues the EAW accepted by the township was commissioned by the developer, International Properties LLC incomplete and was incomplete. The potential environmental impacts warrant further investigation, the group argues.

In the EAW report, Jeffrey Broberg, of Blueline Environmental Advisors in Rochester, noted the Minnesota Department of Natural Resources surveyed the property as part of its Olmsted County Biological Survey and found the area was below the threshold for conservation significance.

In a public comment to the EAW, the DNR acknowledged the land has been classified as below the threshold for biological significance, but encouraged conservation of the remnant upland forest where the heron nest colony was discovered.

“With so few forest remnants remaining, sites such as this should be prioritized for conservation whenever possible,” wrote Melissa Collins, DNR regional environmental assessment ecologist. “The removal of over 17 acres of remnant forest would be a loss of habitat and a significant impact to local wildlife.”

An injunction to halt construction of a road to serve 10 lots with homes was denied in Olmsted County District Court late June. However, the filing temporarily halted construction while the court heard the case. Destruction of nests in use by great blue herons is prohibited under the federal migratory bird treaty act. The nests were active by the time the court made the ruling.

The nest sites are no longer under such protection. The Township Planning Commission meets Monday, Oct. 11, to decide whether to recommend to the township board to approve the general development agreement and whether to rezone the property from agricultural to low density residential.