Nest Box use by Southern Flying Squirrels by C.J. Wong

The Southern Flying Squirrel (Glaucomys volans) is found in the eastern part of the U.S. and southern Canada and south into parts of Mexico. Flying squirrels do not fly. They glide using a flap of skin extending along the side of their body called the Patagium. Flying squirrels are nocturnal as evidenced by their large black eyes. If you live in an area where they are found a good way to see them is by watching your bird feeder at night. Like other squirrels, they love to visit bird feeders for a free snack. Southern flying squirrels only weigh about 3 ounces. Some females reproduce two times per year. The gestation period is 40 days. Litters can be as small as one, but perhaps as large as 6. In southern Illinois I found litters of 2-4 young with a mean litter size of 2.4.

In 1995 I began a project to study the effects of forest fragmentation on the Southern Flying Squirrel. I’ll write more about that project in another issue. In order to complete that project I utilized 300 nest boxes placed in 30 forest fragments in southern Illinois. The nest box design was modified from Woodworking for Wildlife: Homes for Birds and Mammals by Carrol L. Henderson. A similar design can be found on the Michigan Department of Natural Resources website at: http://www.michigandnr.com/publications/pdfs/huntingwildlifehabitat/Landowners_Guide/Habitat_Mgmt/Backyard/Homes_II.htm.

Southern Flying squirrels use nest boxes for different purposes including nesting sites (box has shredded inner tree bark), feeding stations (box has chewed up food such as acorns and hickory nut shells), defecatoria (box is filled with feces) and combination use. If you put up a nest box for flying squirrels in an area where they are common you will likely get some flying squirrels to use your box. In my study 75% of the 300 boxes showed at least some form of use by southern flying squirrels. I found that 22% of my boxes were used for nests only, 15% were used for feeding stations only, 5% were used for defecatoria only, 33% had combination use, and the remaining 25% went unused.

Southern Flying Squirrels will often form aggregations in the winter to help keep warm. I found the largest aggregations in November, December, and January. I also studied the habitat variables surrounding the nest box tree and I’ll report on that in another issue as well.

If you are interested in putting up a nest box for flying squirrels I suggest you find a design you like and build it yourself as commercial suppliers of such a product are hard to come by. If you really don’t want to make one yourself and you can buy a suitable bird box you may be able to just drill a hole on the side about 3.3 cm in diameter. You don’t necessarily have to put up your boxes really high. My boxes were placed at approximately 2.2 meters high.

I recently was introduced to an interesting nest box design, which has three compartments. Although that is not the design used in my study, it is an interesting concept. Mr. Ashley Bracken in Tyler, Texas was kind enough to draft some plans for this box based on information supplied by John C. The plans drafted by Mr. Bracken are included here. [Editor's Note: See Print Version for Design]

See http://sciencelibrarian.tripod.com/SquirrelPage.html for pictures and a more detailed account of this study.

Sources:

Henderson, C.L. 1992. Woodworking for Wildlife. Minnesota Department of Natural Resources, St. Paul, Minnesota. 111 pp.

Woodworth, C.J. 1997. The effects of habitat fragmentation and factors influencing nest box use on the southern flying squirrel (Glaucomys volans) in southern Illinois. M.S. Thesis. Eastern Illinois Univ. Charleston, Illinois. 75 pp.

Wong, C.J. 2004. Nest Box use by Southern Flying Squirrels. Organic Family Magazine 1:25-26