Amazing Animal Fact - Squirrel Migration

I took a walk a few days ago hoping to get good photos of the two squirrel species that live here, the gray squirrel and the fox squirrel (we also have flying squirrels, but they are nocturnal and extremely shy, so we've only seen one in all the years we've lived in Missouri).

At first glance, gray squirrels and fox squirrels look similar, but they differ in color, size, and preferred habitat. Fox squirrels are orangish in color and they weigh, on average, almost twice as much as gray squirrels. Fox squirrels prefer to live near forest edges, whereas gray squirrels prefer to be deep within the forest. To illustrate that, our house is surrounded by forest, so we see at least twenty gray squirrels for every one fox squirrel. To find a fox squirrel on my hike, I had to go to the lake shore a half mile away, where the forest opens up to a wide grassy shoreline. Fox squirrels love to look for food at this forest edge.

Here is a typical gray squirrel:

And here is the only fox squirrel I saw that day (notice the orange color):

Awesome Fact: Gray Squirrel Migration

I saw a social media post where someone mentioned that their grandfather told them stories about massive gray squirrel migrations in the eastern half of the United States, with huge swarms of millions of squirrels on the move. I was extremely skeptical of this because I have never seen more than a few squirrels together, and I certainly haven't seen masses of them crossing highways or swimming rivers. 

So, I dug into this, and guess what—it's real. At least it used to happen. In 1811, Charles Joseph Labrobe wrote about a vast squirrel migration in Ohio: “A countless multitude of squirrels, obeying some great and universal impulse, which none can know but the Spirit that gave them being, left their reckless and gambolling life, and their ancient places of retreat in the north, and were seen pressing forward by tens of thousands in a deep and sober phalanx to the South...”

In Wisconsin in 1842, a gray squirrel migration lasted four weeks and involved nearly a half billion squirrels. Thousands of squirrels were even seen swimming all the way across the Mississippi River.

Similar events were documented throughout the 1800s, and the last really massive squirrel migration was in 1968. 

What's up with that? Here's an explanation. Throughout history, some years had bumper crops of acorns and other food, resulting in a drastic increase of the squirrel population. Then, if the next year saw a big decline in nut production, millions of squirrels had to either starve or leave to find greener pastures (or nuttier forests). 

So, why doesn't it happen anymore? Because the eastern half of the US no longer has vast regions of unbroken forest. The forests are now fragmented, and squirrel density is much lower than it used to be.

I'm afraid we'll probably never have an opportunity to see it, but how cool would it be to witness millions of squirrels on the move?

Photo Credits:
- Fox squirrel and gray squirrel - Stan C. Smith
- Migrating squirrels - Midjourney 6.1