Certain times in history saw mass migrations of squirrels, such as in the 1800s, when they swam the Hudson River between Waterford and Saratoga en masse, with many drowning during the journey, and others dying of exhaustion shortly after.
Since then, other migrations have perplexed naturalists who have raised the question: do squirrels migrate often, or do they stay in the same place? Are these migrations commonplace, or are they due to extreme circumstances?
Migration vs. Emigration
To say that squirrels migrate would be wrong. Wildlife biologists refer to squirrels’ travel habits as “emigration” versus “migration,” because they do not return once they leave home. Real migratory species come back at the change of seasons.
Migration
Animals that migrate do so to follow the rains, such as antelopes, zebra, and wildebeests in the Serengeti (source). In Southeast Asia, bearded pigs migrate to follow seasonal fruit supplies. Many bird species also migrate south for the winter in search of the warmer climate; then, go back to the northern environment in the summer.
Migration means that species leave their homes and go hundreds of miles following food, water, and other survival benefits during the seasons, and then return to their home of origin.
Emigration
Squirrels typically stay in one place and rarely go further than a mile from their homes. If they leave home and go further than 1-2 miles away, there is little to no food in their home area, or there are too many squirrels in one place.
But they rarely, if ever, return home once they leave. Most will either die trying to find food or will become roadkill on highways. As long as there is food, water, and squirrels that are safe from predators, squirrels will stay close to home.
How Far Do Squirrels Travel
During the great migration of 1968, squirrels traveled from the Smokies to the Hudson River (source). In the mass migration in the 1800s, they traveled around 100 miles to find food or escape from an abundant population (source). But by the time they reached their destination, they were too tired to go on, and many died as a result of exhaustion.
Usually, they travel within a few miles of their home before returning. If they go further than that, they don’t often return. Two miles is the absolute maximum distance most travel without too many problems. Some have traveled up to 12 miles and still returned, but that is rare.
Reasons for Emigration
Why do they migrate in the first place? According to Ernest Thompson Seton research which is published in the Journal of Mammalogy, squirrels emigrate due to one of five reasons:
- Floods
- Fire
- Pests
- Famine
- Over-population
- (source)
Most of the migrations occur because of famine and the “great migration of 1968” is a perfect example. In 1967 there was a bumper crop of acorns and chestnuts which resulted in a massive increase in squirrel populations. This was followed by a very low year of food yield in 1968. The combination of over-population and low food supplies resulted in the mass emigration.
Seton believed this also to be the case for squirrel emigrations in the 1800s. They were searching for food when they swam the Hudson. Most never made it, and those that did were either killed by boys with sticks, or out of sheer exhaustion.
When food is abundant, squirrels will generally stay in one place. But when it is scarce, or when there are too many in one place competing for resources, they will leave.
Hibernation vs. Migration
Squirrels stay home in the winter when all of those wimpy birds go South. Different species of squirrels have different ways of surviving cold weather without resorting to migration. One mechanism that all types of squirrels utilize to get through winter without migrating is to over eat in the fall to put on extra layers of fat. The increased bulk provides an extra layer or warmth and serves as a reserve of calories for when food is scarce.
Here is a quick overview of the survival tactics of different types of squirrels.
Ground Squirrels: Ground squirrels like the California Ground Squirrel dig burrows that are used for protection from predators, food storage and a place to wait out the cold months. Some types of ground squirrels go into deep hibernation during winter while others go into a light hibernation called a stupor when their metabolisms and heart rates lower.
Common Tree Squirrels: What most people call tree squirrels are usually Grey, Fox or Pine squirrels. Tree squirrels either build nests, called “dreys” in the branches of a trees or live in abandoned cavities in trees created by woodpeckers that are called “dens”. Tree squirrels will spend most of the winter hunkering down inside their dens with the occasional outing to retrieve the nuts they stashed earlier in the year.
Flying Squirrels: Like the common tree squirrels, Flying squirrels also live in dens. During winter both the Northern and Southern flying squirrels huddle together and lower their body temperature and metabolic rates to conserve energy, and greatly reduce the amount of time they spend looking for food (source).
If you want to help your squirrels make it though winter then give some thought to putting up a nice nesting box as well as a few squirrel feeders!
So, Do Squirrels Migrate?
Squirrels have no desire to leave their homes except in extreme conditions, as they do not have the stamina to go on long journeys. They usually stay close to the burrow, and rarely travel more than 100 yards in any direction. While some squirrels hibernate, most do what humans do–stock up on food in their dens, put on “layers” of fat, and huddle together to stay warm.
When squirrels emigrate, it’s a massive undertaking for them, as it is a dangerous journey, which is why they stay in one place.
