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US Fish & Wildlife Service FieldNotes

Trucking Across the Ice to Help Common Tern Nesting Efforts

Region 3, March 8, 2013
Normal pre-flood common tern nesting activity on Hennepin Island, Mille Lacs National Wildlife Refuge, as captured by a trail camera on June 16, 2012.
Normal pre-flood common tern nesting activity on Hennepin Island, Mille Lacs National Wildlife Refuge, as captured by a trail camera on June 16, 2012. - Photo Credit: n/a
Trail camera photo of the common tern colony on July 5, 2012 at Hennepin Island, Mille Lacs National Wildlife Refuge. With Mille Lacs Lake having high water and the waves washing over much of the terns nesting area only a few tern nests survived.
Trail camera photo of the common tern colony on July 5, 2012 at Hennepin Island, Mille Lacs National Wildlife Refuge. With Mille Lacs Lake having high water and the waves washing over much of the terns nesting area only a few tern nests survived. - Photo Credit: n/a
With the pea rock piled on the ice next to Hennepin Island, Mille Lacs National Wildlife Refuge, Chad Milton, Milton Contracting Inc., ponders his next move when open water was found under the deep snow along the edge of Hennepin Island.
With the pea rock piled on the ice next to Hennepin Island, Mille Lacs National Wildlife Refuge, Chad Milton, Milton Contracting Inc., ponders his next move when open water was found under the deep snow along the edge of Hennepin Island. - Photo Credit: n/a
With a portable bridge in place, borrowed from Mac's Twin Bay Resort, Isle, Minn., the skid steer was able to cross the open water and move snow so the pea rock could be deposited onto Hennepin Island.
With a portable bridge in place, borrowed from Mac's Twin Bay Resort, Isle, Minn., the skid steer was able to cross the open water and move snow so the pea rock could be deposited onto Hennepin Island. - Photo Credit: n/a
With sufficient snow removed from Hennepin Island, Mille Lacs NWR, the skid steer loader was able to deposit 20 yards of pea rock. Due to the deep snow still covering the island the rock will be spread at a later date.
With sufficient snow removed from Hennepin Island, Mille Lacs NWR, the skid steer loader was able to deposit 20 yards of pea rock. Due to the deep snow still covering the island the rock will be spread at a later date. - Photo Credit: n/a
A skid steer loader and a dump truck from Milton Contracting, Inc., travel down the ice road on Lake Mille Lacs to reach Hennepin Island, Mille Lacs National Wildlife Refuge.
A skid steer loader and a dump truck from Milton Contracting, Inc., travel down the ice road on Lake Mille Lacs to reach Hennepin Island, Mille Lacs National Wildlife Refuge. - Photo Credit: n/a

On March 8, 2013, the relatively uncommon common tern received help from an alliance between the Rice Lake National Wildlife Refuge and the Mille Lacs Band of Ojibwe. Tiny Hennepin Island, approximately 0.3 acres in size, is one of two small islands that together form Mille Lacs Refuge, the smallest refuge out of 561 refuges in the National Wildlife Refuge System. The entire refuge is a mere half acre in size. In spite of its small size, Hennepin Island stands tall as an important nesting site for the common tern within the state of Minnesota. There are at the present time only five known nesting colonies in the state. With an average of 167 tern pairs over the last ten years the colony on Hennepin Island is one of the largest colonies in the state.

The common tern is a ground nesting species that prefers to build their nest in course sand or small rock. Their nest is nothing more than a depression in the ground. Their eggs are perfectly camouflaged in the sand or small rocks. Due to Hennepin Island's small size and low profile, the small rocks are prone to washing away during summer storms or scraped off by the ice when the wind and waves push ice sheets onto the island during early spring.

Last June's torrential rains and subsequent high lake levels were especially devastating for the nesting terns. Not only did it wash away the small rocks but it also washed away countless eggs and young tern. Due to weekly population monitoring it was determined that there were 185 tern pairs / nests and only 17 young terns reached an age capable of taking flight.

In hopes of less extreme weather this summer, Rice Lake Refuge and the Mille Lacs Band of Ojibwe agreed to work together to improve nesting conditions for the common tern. The refuge bought 20 yards of pea rock and the Mille Lacs Band hired Milton Contracting Inc., a local contractor, to haul the rock to the island. Another valuable partner in this effort emerged as well. Mac's Twin Bay Resort, Isle, Minn. agreed to have the pea rock stockpiled in their parking lot for the contractor to haul. The resort also plowed open the ice road from their resort to Hennepin Island, a distance of nearly two miles. And once the rock was piled on the ice waiting to be moved onto the island it was discovered that there was open water hiding under deep snow along the edge of the island, making it impossible for the rock to reach the island. Mack's Twin Bay Resort saved the day when they offered the use of their portable bridge so the contractor's skid steer loader could cross the open water and deposit the pea rock on the island.

It was due to some long standing partnerships as well as new partnerships that made this difficult project successful. But due to the deep snow still blanketing Hennepin Island it wasn't possible to spread the pea rock. The Mille Lacs Band and the refuge will soon partner again to spread the pea rock prior to common tern nesting activities.

Contact Info: Walt Ford, 218-768-2402, walt_ford@fws.gov