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Loon Nesting Program

Big Mantrap Lake boasts a high population of loons due in part to the lakes many bays and points, but a lot of it has to do with the lakes volunteer "Looners" who run the Loon Nesting Program.  Details on the program and nesting platforms can be found below.

About half the nesting pairs on Big Mantrap are natural nesters and half use the nesting rafts (also called platforms).  The nesting rafts are backups in the event of high water or predation. 

There is no guarantee loons will use this raft design.

Researchers have discovered that territorial male and female loons are replaced every 6 or 7 years. Male loons select the nest site. Loons may have nested successfully on a raft for many years, then the new male may select a natural nest site within the territory.


Big Mantrap Lake is 1556 acres in size, with more than 21 miles of irregular shoreline, including five islands and many bays and coves.  25-30 potential loon nesting territories have been identified.  At this time we average 24 nesting pairs use the lake between natural and man made sites.  

Loon nesting rafts are set immediately the day the ice goes out and removed three weeks after the chicks hatch. The rafts are removed so that the natural beauty of the lake is not impaired.  Refurbishing the nests, setting them out, and removing them, requires the efforts of a number of volunteers.

The Big Mantrap Lake Loon Nesting Program began in 1990 with rafts based on the Minnesota DNR WOODWORKING FOR WILDLIFE model. Our raft fabrication materials have shifted from wood to plastic and now aluminum.  Light weight aluminum nesting rafts best suit the needs of our lake, because of the number of rafts needed and the seven mile length of the lake.  Two rafts with anchors and buoys can be hauled in and out of a 14 foot boat. 

Type A Raft with carpet in place

Type A Raft with carpet in place

Type A Raft with Trail Camera attached

Type A Raft with Trail Camera attached

Big Mantrap Raft Design Features:

  • Strong welded integral construction

  • Removable canopy frame and screen

  • Easy access ramp for adults and chicks

  • Nest ring

  • Light weight

  • Resistance to corrosion

  • Dry natural vegetation for nest

  • Resting area

  • Seaworthy in rough water

Above the Type A Raft.   We use the cameras to monitor for predators and confirm number of eggs; when laid and when hatched.

Below the Type B Raft.  We use them in areas protected from heavy wind.  They are placed near natural nests that have a history of predation, away from shore 15 to 50 feet.  Canopy is normally added the year after loons begin using them.  The surface is covered with outdoor carpet glued to the aluminum surface..

Type B Raft with Trail Camera attached

Type B Raft with Trail Camera attached

b raft.jpg

Retired Loon Nesting Rafts Available

Loon nesting raft design is an ongoing project.  Recently the changes have been minor.  As new rafts are added to the collection, we retire rafts of earlier designs.  These successfully used rafts are available to lakes wanting to start a loon program.

We also have done our best to capture the step by step directions from our old website that outlined raft assembly several years ago.  That guide can be found here.


Ongoing Development

The development of this raft is due to the work and observations of numbers of Big Mantrap Lake residents and fabricators.  Experimenting on hunches and learning from errors in judgment has been our design process.  Resident's donations and memorials pay for the fabrication of new rafts and supplies. Each year we think that the evolution of the nesting raft is complete only to find that there are still other aspects needing attention.  We welcome your questions and suggestions for continuing raft improvement.  You are also welcome to visit our nesting raft "marina" on Big Mantrap Lake.  We wish you success with your loon propagation.

Contact Us

For questions regarding the Loon efforts on Big Mantrap Lake please contact Barry Guptill, (218) 732-9039 or guptillbarry@gmail.com

For information on the raft construction, Duane Petterson may be reached at (507) 451-0527 or dspetterson@gmail.com