Ruffed Grouse Snow Beds

When the snow gets deep and temperatures go down, ruffed grouse have a wonderful way of staying warm overnight. They can’t climb down into woodchuck burrows the way rabbits do, or follow narrow openings down to warmer depths like weasels. And they don’t curl up with their tails over their heads like foxes. But they can fly, and that allows for a unique strategy. In mid-flight, a grouse tucks its wings close to its body and dives into the snow. Once submerged all it takes is a few wiggles to shape a perfectly formed and well insulated snow cave.

I found the grouse bed pictured below back in November after an unusually early snowstorm. The place where the bird plunged into the snow is on the left, and the exit side of the bed is at the lower right. The trail the bird made as it walked away extends toward the top of the frame.

Here’s the same grouse bed from another angle–the entry is now at the top of the frame and the exit is at the bottom. The cavity where the bird spent the night is located under the undisturbed snow between the two holes. If you could peer down into the lower hole you would see a chamber roughly the shape of the grouse’s body.

If you can’t picture how it all happened you’re probably not alone. One of the keys to interpreting nature’s messages is to go back in time to the beginning of the incident and work your way through to the end.

Consider what happens when you toss a ball into soft, fluffy snow. The ball disappears and leaves nothing but a small depression where it went in. It’s only when you grope around trying to find the ball that more of the snow gets disturbed. A similar situation occurs with a grouse’s snow bed. Once the bird disappears under the snow, the only sign on the surface is a depression where it went in. The grouse can’t be seen, and there’s smooth, undisturbed snow everywhere except for a hollow of tossed snow. It’s not until the next morning, when the bird wakes up and begins to wriggle forward and upward, that the snow around it is disturbed and at least one other hole in the snow appears.

In the photo above, you can see some dark material in the lower hole. A close-up shows that the dark material in the cavity is scat. Grouse typically defecate before they begin to work their way out of the their snow cave.

If the snow isn’t deep enough–or soft enough–for a plunge, grouse rest in surface beds like the one shown in the photo below. On the right side of the photo you can see a hollowed out, grouse-body-sized depression. The usual scat pile sits in the bottom of the bed, and the tracks made by the bird as it walked away can be seen heading toward the left. The scat in the surface bed (and also in the snow cave in the preceding photos) is dry and fibrous, the type of scat produced from the grouse’s normal winter diet of buds, twigs, and catkins. But in the photo below there’s another kind of scat, lying roughly in the center. This wetter, softer scat is called caecal scat, and it’s produced when a grouse eats higher quality food, such as the cambium layer of woody plants. More nutritious food goes through an additional digestive process in specialized intestinal pouches called caeca.

I marvel at the adaptations that ruffed grouse–and other creatures–have for coping with the challenges of winter. And I love the way such behaviors become more real when when I can see and understand the actual evidence. It’s worth the effort to parse out the story and see what birds and animals really do to survive.