North American flying squirrels employ several nest types, and
typically will use several nest types during their lifetime.
Individuals may use a nest just once or for much longer periods,
depending upon factors such as availability, sex, time of year,
predator avoidance, parasite load, disturbance, water infiltration, and
that are employed during night forays, as "one-offs" during natal
dispersion, or as diurnal denning sites are called
refugia nests. Shelters that are used to raise young are called natal
nests. Shelters that are employed by a number of related or unrelated
individuals during winter months are called aggregate nests.
As a rule, southern flying squirrels are somewhat less than fastidious
when it comes to "bathroom behaviour", and will often soil their own
nests. There is no evidence on record of this
behaviour among northern flying squirrels.
Southern flying squirrels will also take food into their diurnal denning nests, where
this behaviour is not found with northern flying squirrels, although
both employ the use of nocturnal refugia nests to consume foodstuffs.
Materials used to make nests varies wildly and depends upon
what suitable materials are present in a particular squirrel's
immediate geographic location. These materials can include strippable
bark (i.e. cedar, birch, wild grape); grasses; mosses; lichens; found
animal fur; found bird feathers; small twigs; tree leaves (deciduous
and coniferous); man-made materials (i.e. attic insulation, newspaper).
depth, or loft, varies according to type of use required, season, and
sex of the nest builder. Below are two representative examples which
display the difference between a late spring natal nest (left) built by
a gravid female northern flying squirrel and a late spring dirunal refuge
nest built by a solitary male northern flying squirrel (right). This
natal nest is almost 700 percent larger by volume than the solitary
male nest. Additionally, the solitary male nest material has not been
finely shredded as is the case with the natal nest material, both of
which consist of (mostly) eastern white cedar bark.
Eastern white cedar tree bark, leaves and wood contain varying levels
of water repellent oils and insecticidal oils (specifically thujone a
-thujone, b -thujone and fenchone). These two important properties have
not been overlooked by flying squirrels. In our area of study, (Grey
and Bruce counties, Ontario, Canada), every single nest built by
northern flying squirrels consists almost wholly of eastern white cedar
bark (some cedar leaves are present in some nests. Also found in the
nest material is sphagnum moss, grasses, fur, feathers and
Typical natal nest (left) and solitary male nest (right)
Scale shown is metric (mm/cm)
native North American groups traditionally employed red and flying
squirrel nesting material as an absorbant lining for
diapers. Somehow we doubt Procter & Gamble will bring
a Squirrel Nest Pampers diaper to market!