It seems inevitable, just when we get used to enjoying the balmy days of
summer, fall starts creeping up on us. For wildlife it means many changes. For
early migrants it is time to close up the summer residence and head south. These
migrations include seemingly almost impossible feats.
Young Kirtland’s warblers begin migration from the jack pine barrens of
northern Michigan before their parents. In most cases, these young birds have
never been more than a mile from their nest but will travel 1200 miles without
adult supervision to their Bahamian wintering grounds.
Monarch butterflies also fly thousands of miles to a few valleys in Central
America. Here they congregate in masses covering the branches like a living
carpet. More amazing, these butterflies are not necessarily the offspring of the
butterflies which returned north last spring, but in some cases are the second
or third generation.
Everything seems to kick into high gear. Mice and squirrels furiously gather
nuts and seeds for storage. (I know this because this is also the time that
locating stashes of dog chow stored away in my garage is a daily event.)
At the same time, these animals must expend energy to thicken their coats for
the long, cold winter days. Many animals have two types of fur. Stiff guard
hairs make up the over layers providing protection. In the case of aquatic
animals like beaver, muskrats, and otter this layer of fur is oiled to keep
water away from their bodies. The underfur is a soft fluffy layer that captures
air and provides insulation for the animal.
Other animals like bear and woodchucks have spent the last few months eating
as much as possible to gain weight. Seeing them you would think they were not
much more than a pelt covering a tub of fat. They will spend the next few months
sleeping or hibernating, losing all of the fat stored-up over the past summer.
Keep an eye out during the warm rains of late summer and early fall. That
moving road or path ahead just might be a migration of frogs or salamanders
heading to their wintering wetlands. About this time, I usually end up with one
or two gray tree frogs peering through the screen door.
Once they have reached their hibernation site, these amphibians actually bury
themselves alive! Some will dig below the water line of lakes, others just above
the water table. Their bodies will reach near freezing temperatures.
The fall is a time of many changes. Many things are happening right under our
noses. While changing your storm windows or cleaning the remains of this year's
vegetable garden, take a few extra moments and see what changes you can find.