The Great Moose Migration

It’s that time again! Moose are gathering in clusters in the wooded areas around Kullberg, in northern Sweden. The Ångerman River poses a major obstacle along their migration route, and here they gather at about the same time every year – just as they have for thousands of years. Some cross quickly, others take their time. Some choose to swim across, while others dip a hoof and turn back to find another route.
Where are they headed—and where have they come from? Let’s find out.

 

At Kullberg, the landscape has drawn moose along their migration route for thousands of years – evidence of this can be found in ancient pitfall systems, rock carvings, and archaeological excavations.

Many of the moose we’ll soon sneak a peek at through SVT’s cameras are on the move; making a journey from their winter grounds to the area where they’ll stay during the summer and part of the fall.

For some, the journey has just begun, others are almost there – and for a few, the forests around Kullberg are home year-round.

 

Photo: Jesper Stenmark

 

From late April to late May, most migratory moose move from their winter to summer areas. Many people believe that moose, like many reindeer, migrate between the coast and the mountains, but they don’t usually go that far.

Most migratory moose in the north travel between 30 and 90 kilometers (the longest migration we’ve measured is a full 200 kilometers!). The few moose that migrate in southern Sweden move about 6 to 10 kilometers.

 

For female moose (cows), the spring migration tends to be fairly quick. After just one to three weeks, the cow has reached the summer area where she’ll raise her calf.

When spring growth begins to color the landscape, she’s already there. That’s when the vegetation is richest in nutrients, just what she needs to regain her strength and nurse her calf. Nature is remarkably well-timed.

“Bulls aren’t in as much of a hurry – they don’t have calves to raise and aren’t dependent on finding a suitable calving spot,” says Wiebke Neumann, wildlife ecologist at SLU.

 

Photo: SVT

Then, when autumn gives way to winter, it’s time again. From mid-November to mid-January, most migratory moose begin their journey back to their wintering grounds. This trip takes longer and the moose are more spread out.

“For some moose, it can take six to eight weeks from the time they leave the summer area until they reach their winter habitat. Why rush? That would only waste energy, which is better saved for the harsh winter,” says Göran Ericsson, professor of wildlife ecology at SLU.

Climate has a big influence on when – or even if – moose choose to move. A milder climate with shorter snow cover periods can lead to moose staying longer in their summer areas, or not migrating at all.

 

Photo: Jörgen Wiklund

 

Not all moose migrate. Some seem to see no point in the whole hassle of switching homes and choose instead to stay in the same area their whole life.

The share of migratory moose, when they set off, and how far they travel varies depending on where in Sweden they live, and between individuals in the same area.

There’s a general rule for moose migration: the farther north you go, the more moose migrate – and the longer their journeys. In the south, it’s the opposite: more moose are stationary, and those who do migrate travel shorter distances.

 

As we move closer to the mountains, seasonal changes in food availability become more dramatic. The climate here is harsh, and the seasons sharply defined.

In these areas, the landscape clearly guides the moose: river valleys between mountain peaks carve migration routes through the terrain, and most animals follow the vegetation shifts along these paths. But moose also migrate vertically, up and down the mountains.

“In Nikkaluokta, many moose migrate uphill. They often spend late winter in the river valleys, but in summer, they head for higher elevations and stay up on the mountains until December, when they gradually begin moving back down,” says Wiebke Neumann.

 

Photo: Susanna Bergström, SLU

 

In southern Sweden or the inland areas of the north, the landscape is flatter and attractive habitats are not as clearly structured. Here, migration can occur in all directions, and the seasonal changes aren’t as stark – food may be available year-round, so the moose don’t need to move far.

So, what counts as ‘home’ for a moose? A moose has a home range where it spends its life. For migratory moose, this includes several seasonal ranges, since they spend summer and fall in a different area than winter.

 

A home range can be quite large, but just as humans go to the store to buy food and lie down in bed to rest, moose use certain parts of their range more than others. The areas where a moose spends more than half its time are called its core areas.

“In winter, moose are concentrated in parts of the landscape where food and climate conditions are optimal, while in summer they spread out more evenly across the terrain,” says Wiebke Neumann.

 

 

Photo: SVT

 

Let’s return to Kullberg, where the slow tv show is recorded – to the pines and berry shrubs that will soon nourish the moose as they rest briefly before continuing their journey.

But one question remains unanswered: why? If moose migrate to take advantage of the landscape, why don’t they go farther? Why would food and shelter be better 10, 50 or even 100 kilometers away?

“To understand what drives moose migration, we can’t just look at environmental factors or individual animals. Migration is part of moose culture,” says Wiebke Neumann.

 

Migration is a socially learned behavior, passed down from cow to calf, but also between unrelated moose. The older generations show the way.

Some moose learn to migrate; others learn to stay. And some choose their own path—doing the opposite of what their mother taught them.

So what’s the smarter choice: to stay or to move?

“Over time, both strategies work equally well. We haven’t seen any difference in physical condition between migratory and stationary moose,” says Wiebke Neumann.

 

 

 

Researchers from the Swedish University of Agricultural Sciences (SLU) have been part of SVT’s production The Great Moose Migration since day one – acting as experts both behind and in front of the cameras. Every year, they help audiences understand the science behind this spectacular wildlife event.

If you have questions or would like to get in touch with one of our researchers, don’t hesitate to contact us.