Escaping Winter's Cold

     With the extreme cold of the first week in January, 2018, I again wondered how wildlife in southeastern Pennsylvania, as elsewhere, was finding shelter from that cold.  I remember seeing critters, including mallard ducks and white-tailed deer huddling on the sunny side of stone walls and wooded slopes.  Some kinds of birds, including mourning doves, dark-eyed juncos and certain kinds of hawks and owls, "hole up" in densely needled spruce trees to avoid cold wind, the owls by day.  I have stepped into patches of half-grown spruces and noticed they block the wind quite well, making me feel warmer in those clumps of conifers.  Other species of birds here retreat to abandoned woodpecker holes and other tree hollows to avoid winter's cold.  They include two types of chickadees, tufted titmice, white breasted nuthatches, eastern bluebirds, American kestrels and screech owls.
     Several kinds of winter-active mammals also escape from winter's cold.  Eastern moles and star-nosed moles are protected in their underground tunnels, while short-tailed shrews hunt mice and invertebrates under carpets of fallen leaves.  Long-tailed weasels live and hunt mice in crevices in wood piles, brush heaps and rock walls, while little brown bats sleep in caves, barns and other sheltering places.  And cottontail rabbits, striped skunks, opossums and raccoons crawl into deserted wood chuck holes, hollow logs, brush piles, tree cavities and under outdoor sheds on lawns to get away from the cold.
     But rodents have the most fascinating ways of staying out of cold, winter winds.  Gray squirrels are the most obvious of their family because they live in forests, wood lots and older suburban areas and parks with their many tall trees.  Gray squirrels have two kinds of homes- tree cavities and basketball-sized structures they make themselves of twigs and dead leaves and place in forks of twigs for support.  Both shelters, which are easily seen in bare deciduous trees in winter, provide insulation against cold winds.     
     The nocturnal flying squirrels also live in tree cavities, and attics in cabins and houses in the woods.  There they have protection from cold winds during the day.
     Wood chucks and eastern chipmunks spend the whole winter in their underground burrows.  Chucks dig out their own homes that has a few exits so those big ground squirrels don't get trapped by predators in their own tunnels.  Chucks put on much weight by eating lots of vegetation during summer and autumn and live off their fat through their long winter's sleep in their underground dens.
     Chipmunks live in underground dens, and, in fall, store many nuts and seeds in their homes to consume through winter.  Each chippie sleeps in a chamber, but awakens frequently to ingest nuts and seeds in a storage room, then goes back to sleep in its slumber room.
     Two kinds of mice, deer mice and field mice, or field voles, make simple shelters that protect them from the elements.  Some deer mice live in tree cavities, but others of that lovely species of mouse build roofs of chewed grass and thistle and milkweed down on abandoned birds' nests in shrubbery.  Each mouse chews a hole in the side of its former bird nursery for an entrance.  Both kinds of shelters are well insulated. 
     Field voles chew dried grass to make nests on the ground at the base of tall grass in meadows, fields and along rural roadsides.  These mice move about through tunnels of chewed grass under snow covers, which protect them from predators and the elements.  But when the snow melts, those networks of vole tunnels are visible, and the voles are more exposed.
     Muskrats make two types of homes, depending on where they live.  They pile up cattail stalks in shallow ponds to live in.  And they dig burrow entrances at the usual water line of streams and tunnel up to dry, insulated living chambers in streambanks.  Mink kill and eat some muskrats and live in the homes of their victims.  
     Beavers also make two kinds of homes, log and limb ones heaped on mud platforms in the middle of ponds they created by damming streams, and burrows they dig into streambanks at the normal water level of creeks and rivers.  Those beaver homes, like those of many rodents, protect them from predators and the elements, particularly in winter.
     Many kinds of birds and mammals, especially rodents, have ways to insulate themselves from winter's cold and other potential problems.  These are just part of the ways wildlife sustains their lives during adverse conditions.