Plenty of Rhode Islanders have begun making plans
to migrate south for the winter. For almost all, the move is entirely about the
weather. They’re trying to avoid the cold and snow and ice that invariably
comes with winter in the Ocean State.
Lots of different kinds of wildlife are preparing
to make a similar move, and while the weather has a lot to do with it, their
migration is often driven by the availability of food.
Birds are the animals most frequently associated
with migration. Every fall, billions of birds take off from Canada and the
northern U.S. and head to South America, Central America, the Caribbean and the
southern states in search of a reliable food supply. Most are bug eaters
seeking a location where insects are abundant during the winter months.
Seed eating birds don’t usually migrate as far as
the bug eaters. Many sparrows, finches
and other seed-eaters end their
migration in southern New England, knowing that seeds and berries – and bird
feeders – are abundant here during the winter. Those species also have unique
physiological adaptations to weather the weather here.
But birds aren’t the only animals for whom
migration is a successful strategy. And not all travel in the same southerly
direction.
Bats for instance. Those that roost in trees for
the winter, like red bats and hoary bats, do so in the southern U.S. after a
short fall migration. But those that hibernate in caves, including little brown
bats and tricolored bats, migrate north from Rhode Island to caves and mines in
New Hampshire, Vermont and upstate New York where the temperatures remain
steady at about 40 degrees throughout the season. Many big brown bats don’t
migrate at all, choosing instead to spend the winter here with the rest of us.
Some butterflies and dragonflies are in the midst
of migration right now. Monarchs are the most famous of them all, traveling to
the mountains of central Mexico to winter. But it’s not uncommon to see swarms
of dragonflies like green darners or wandering gliders along the coast or even
out over the ocean at this time of year as they seek warmer climes.
Reptiles and amphibians in our area are on the
move now, too, though their movements are comparatively short. Some frogs just
move from local ponds to nearby forested upland areas, while others seek out a
comfortable spot in the mud or along a stream. Garter snakes often migrate to
communal dens underground to hibernate.
In many mountainous states, especially in the West,
migration occurs in a vertical direction. Mammals like elk, mountain goats and
bighorn sheep migrate from high elevations down to lowlands to escape winter’s
icy conditions to where they can find food more easily.
Migration happens in the ocean environment, as
well. Harbor seals are now beginning to arrive in Narragansett Bay after
breeding along the coast of Maine and the Canadian Maritimes. Humpback whales
are on their way to the Caribbean to breed during the winter months. Bluefish
and striped bass are headed south to warmer waters, too, and horseshoe crabs
are slowly making their way to deep water after summering along the coast.
So as you make your winter migration – regardless
of where your plans take you – don’t be surprised if you’re joined by some of
Rhode Island’s wild summer residents.
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