Winter Food Webs: The Snow Layer That Connects Everything

Snow Isn’t Empty. It’s a Roof.

A fresh snowfall can trick us into thinking everything paused.

But snow doesn’t erase life—it reorganizes it.

It acts like a blanket and a ceiling at the same time, creating a hidden world underneath and a brand-new “map” on top. Suddenly, ecosystems aren’t just horizontal (forest to field). They’re vertical.

That’s the winter secret:

The snow layer connects everything.

What moves under it feeds what hunts over it. What survives in it supports what survives beyond it. One layer becomes the meeting point for predator and prey, energy and hunger, shelter and risk.

And if you want students to truly understand winter ecology, don’t start with “hibernation.”
Start with the question winter asks every animal:

Where do you get energy when the world is cold?

The 3-Layer Winter Food Web (The “Stacked Ecosystem”)

Think of winter as a three-story building:

1) Above the Snow (The Sky & Perch Level)

This is the predator zone—where hunters search, listen, glide, and scan.

Who lives here?

Owls (barn owls, great horned owls, snowy owls regionally)
Hawks (some still hunt in winter)
Coyotes and wolves moving across open areas
Ravens and other scavengers

What matters up here?

visibility
wind
perches
and most importantly: prey availability

Owls are the best “winter food web poster child” because they link the layers beautifully: they hunt over snow… but their food is often moving below it.

2) On the Snow (The Surface Level)

This is the travel-and-risk zone. Tracks, trails, and exposed movement happen here.

Who uses it?

Rabbits and hares bounding between cover
Foxes and coyotes trotting along edges
Deer traveling between bedding and browsing
Weasels popping in and out
Humans… which matters, because we pack trails that animals often use too

What happens here?
This is where winter shows you behavior:

who hugs the brush line
who crosses the open
who took the “easy route”
who got chased

If snow is nature’s notebook, this is the page students can read without any special equipment.

3) Under the Snow (The Subnivean Zone)

This is the hidden engine room of winter.

The subnivean zone is the space between the ground and the snowpack. It’s insulated. It’s warmer than the air above. It’s where small mammals can move, feed, and avoid the worst of winter—at least until predators find them.

Who lives here?

voles
mice
shrews
insects and overwintering invertebrates
seeds and plant matter that becomes winter fuel

Why it matters:
This layer is the base of many winter food webs. If the subnivean zone is healthy, prey survives. If prey survives, predators can too.

So snow isn’t just weather.
Snow is habitat infrastructure.

The Big Connection: Owls Are the “Thread” Between Layers

Owls are built for winter’s stacked ecosystem.

They hunt over fields and edges, but they’re often targeting animals that:

move in tunnels under snow
pop up briefly on the surface
or travel along cover lines

That’s why owl pellets are such a powerful teaching tool: they’re basically a printed receipt of the winter food web.

Pellets show:

what prey was available
what habitat is supporting
what trophic links are active right now

In other words: students don’t just hear the food web.
They can literally hold the evidence.

Fun Fact

Snow depth can change the entire predator-prey balance. In deeper snow, prey may move more under the surface, and predators may shift hunting strategies—or burn more energy trying. Winter food webs are dynamic, not static.

Classroom Connection: Build the 3-Layer Winter Web (Above / On / Under)

This is a high-impact activity because it turns “food web” from a flat diagram into something students can see as a system.

Materials

3 sheets of paper (or one large poster divided into 3 bands)
markers
optional: printed animal cards
optional: string/yarn for connections

Step 1: Create the three layers
Label:

Above Snow
On Snow
Under Snow

Step 2: Add organisms to each layer
Give students a starter set like:

Under Snow: vole, mouse, shrew, seeds/grass
On Snow: rabbit, deer, fox
Above Snow: barn owl, great horned owl, hawk, coyote

Step 3: Draw energy arrows (who eats whom)
Have students connect:

Seeds/grass → vole/mouse
Vole/mouse → owl
Rabbit → owl / fox
Mouse → fox
Deer (carcass) → scavengers (optional)

Step 4: Add “winter pressure” cards (the thinking step)
Give each group a condition and have them update the web:

“Deep snow this week”
“Icy crust on top”
“No perches near the field”
“Rodent numbers drop”
“A packed human trail appears”

Ask:

Which connections weaken?
Which predators struggle?
Which animals shift layers?

This is where students stop memorizing and start reasoning.

Extension: CER Mini-Write

Claim: Which layer is most important for the whole winter web?
Evidence: Use at least 3 connections from your diagram.
Reasoning: Explain how energy moves through the layers.

Product Spotlight: Owl Pellets + Prey Charts/Posters

If you want this lesson to stick, pair the web with a real-world data source.

Owl Pellets (the evidence)
Owl pellets let students:

identify skulls and bones
count prey types
compare pellets across groups
infer what the local habitat supports

That turns your 3-layer web into something measurable: “What prey shows up most? What does that mean for the under-snow community?”

Prey charts/posters (the visual anchor)

A prey ID chart or classroom poster makes the jump from “bones” to “species” way smoother—especially for younger grades and English learners. It also helps students connect the pellet lab back to the layered web on the wall.

Teacher Takeaway

Winter ecosystems aren’t frozen in place.

They’re stacked.

And snow is the layer that connects everything:

shelter below
movement on top
hunting above

Teach students that winter is a vertical food web, and you’ll watch their thinking change. They stop seeing snow as “empty season” and start seeing it as a living system—quiet, layered, and working hard.

Because in winter, the question isn’t “What lives here?”
It’s:

“What connects to what… and how do we know?”