Weather and Wildlife: Expect the Unexpected

This past winter, while leading my annual Winter Yellowstone Workshop, we came across something extraordinary. This particular workshop was my 30th winter trip I had led in the park. Over the years, I have spent hundreds of hours tracking bobcats, and helping clients find and photograph these elusive cats. But never had I found one who had killed a deer.

We weren’t the only ones to photograph this situation, of course. And while we set in the snow behind our lenses, theories as to how this may have happened spewed from others who had arrived like so much steam and water gushing out of Old Faithful.

“There’s no way that cat took down the deer. She must have fallen off the cliff above,” said one person.

Within minutes, this became the official story relayed to all newcomers on the scene. Another person would come walking up, and make a comment about how they can’t believe a bobcat killed a deer. Immediately the party line was repeated. “Oh no, the deer fell off the cliff above and broke her back. The cat just happened to find her there.”

Of course, no one saw the situation happen.

Nobody was there to see if the deer fell or if the cat killed her.

It didn’t really matter one way or the other. In front of us was a large bobcat sitting beside the throat of a dead mule deer in the snow. Blood stained white where they cat had done what cats do and strangled the deer with their teeth.

Winter brings change for all

As the temperature plumets, as snow begins to fall and accumulate (if it’s a place where snow falls and accumulates), as insects disappear, and food sources become scarce, and tomorrow is never guaranteed, life adapts in new and unique ways. 

In the summer months, bobcats, like all predators, busy themselves with the ease abundance. Ground squirrels and red squirrels are easy pickings in the Yellowstone area. Elsewhere it’s rabbits, insects, snakes, birds, mice, and voles.

But come winter, the ground squirrels are hibernating, the insects have died back, most birds have migrated, mice and voles are eking out a living beneath the snow and out of reach for most predators, at least in this place, and rabbits or hares are in places where the snow is too deep for bobcats to hunt and only Canada lynx dare tread. 

Here in the Yellowstone ecosystem, where geothermal features keep several rivers and lakes ice free through the winter, waterfowl and other animals gather in mass. The warmth of the water brings life. And bobcats can thrive atop the Yellowstone Plateau through the winter for this very reason.

But to find food, they do the unthinkable for cats – they jump in the water after ducks, geese, swans, and muskrats.

This is something I have talked about many times before, that is, the unique hunting techniques of bobcats in the region and how knowledge of their behavior shift in the winter has filled entire hard drives with photographs for me over the years.  

Yet, what I find interesting about this, that bobcats use logjams along ice free rivers and creeks as ambush points, is not something we have a difficult time believing. These cats hide themselves in the jumble of logs only to launch through the air and on top of an unsuspecting Rocky Mountain Trumpeter Swan that happens to swim by. Here, they cling to the throat of the swan in hopes of strangling or drowning the bird, all while they themselves are usually upside down and submerged in the water as they are swept downstream.

Take this information and filter it through everything you think you know about cats.

It borders on the absurd.

Yet, this is an accepted fact of life here on the Yellowstone Plateau. So, why do we struggle with the idea of a bobcat preying on a 150lb mule deer?

Every animal that is cold adapted, that like us is the progeny of the last ice age, has their winter tricks up their sleeve.

Great gray owls sit atop broken snags and adjust their facial muscles to expand or contract the giant satellite like dish of feathers on their face. This is done to broaden or narrow the area they are listening to. The sound waves then travel to their ears which are positioned asymmetrically in order to better triangulate the exact location of the faint sound of a red-back meadow vole 2 feet beneath the snow and a hundred yards away. Once they have homed in on the location of the sound, they swoop down but pause mid-air and hover above the snow with faces pointed downward. They do this to compensate for the sound mirage caused by the refraction of the soundwaves traveling up through the snow. Once all is recalculated, they plunge fists first into the depths, collapsing the tunnels through the snow around the vole, effectively trapping them in a snowy tomb.

Now THAT is extraordinary.

Understanding the importance of sound waves and how it travels up through the snow, you can identify key areas that these birds will hunt in and why they prefer small meadows, muskegs, and powerline trails through the forest.

Boreal owls share a home with great grays. But thanks to their size (they are so small they nest inside woodpecker cavities), they are unable to punch through 2 feet of snow like their bigger cousins. Instead, come winter, they shift their hunting to the base of trees.

As the snow begins to accumulate in the boreal forest, great open pits form beneath the conifer trees. Thanks to the heat generated by the tree and the way in which limbs and needles of these species shelter the ground beneath, tree-wells form like so many thousands of craters in the snow across a forest. Here, the snow is only a few inches deep if there is snow at all. And the winter survival strategy of boreal owls becomes focused on hunting these tree-wells through the boreal forest.

As a wildlife photographer, you can use this to help predict areas of forest where boreal owls will likely hold in higher numbers due to the presence of tree-wells.

Red foxes, like great gray and boreal owls, also hunt by sound. But this is only half of the story. 

Researchers began noticing that red foxes tended to hunted in a predictable grid like pattern and decided to conduct a massive study of this species all across North America and Eurasia. In all, some 80 different researchers around the world joined in what would become a truly international effort to understand how red foxes hunted in the winter. The results blew everyone away.

In the winter months, when red foxes are “mousing” in 1 – 2 feet of snow, the success rate at capturing rodents was above 70% so long as the fox was facing either north or south. In any other direction, that success rate dropped to 15%.

What researchers stumbled upon was the fact that in addition to listening for the sounds of voles beneath the snow like a great gray owl, red foxes were also using the Earth’s magnetic field as a range finder to judge distance. While a great gray owl hovers directly above the snow to adjust for the sound mirage, a red fox sits at ground level and has to calculate the distance from herself to the sound she is hearing to within inches. Like birds migrating across hemispheres or whales moving across entire ocean basins, red foxes have the ability to tap into the Earth’s magnetic field – only they use it to help them increase their success rates at catching food.

If you know this, and you find a fox hunting in an open meadow during the winter, you can predict the grid pattern the fox is going to hunt – always moving in a north or south fashion and set yourself up accordingly.

Circling back to bobcats, there have long been stories of these little cats killing deer. Like the other photographers in Yellowstone, biologists generally lumped these into the same category as bigfoot sightings.

That is, until two separate studies were done across New England and the Upper Great Lakes region back in the 1950s. The results of both showed that not only was deer the number one source of protein for these cats in the winter, but field biologists were also able to consistently find bobcat killed deer carcasses throughout the forests where tracks in the snow revealed the story. And much like how the cats of Yellowstone used ambush points along rivers to hunt, bobcats were often doing the same thing near well-traveled game trails used by deer.

Want to photograph bobcats this winter? Find their tracks and following them into the forest until they intersect with well used game trails. From there, begin locating potential ambush points.

Everything is different in the winter. When temperatures drop and food sources become scarce, whether you live in Scotland or St. Louis, it’s important to set aside all the assumptions of how animals make a living. Life adapts. It changes. It evolves the ability to listen to and detect faint sounds beneath 2 feet of snow from a hundred yards away. It learns to tap into and use the Earth’s magnetic field. And it switches diets, learning that precisely placed teeth can crush the throat of a deer whose flesh will sustain life for weeks of winter to come.

I think this is the reason I love winter so much. It’s the change. It’s the unique adaptations. And as a working wildlife photographer, learning how life changes and adapts to this season creates a challenge both intellectually and physically that is worth rising to the occasion for.

It’s important to keep in mind that when it comes to finding and photographing wildlife this season, the more we understand about the subjects we seek, the better naturalist we are, the better wildlife photographer we will be.

- Jared Lloyd

So important is understanding how weather and the changing season impacts our ability to find and photograph wildlife, that I’m working on a feature article about this topic for the upcoming issue of PhotoWILD Magazine. From finding great gray owls to bobcats, from the tundra to the tropics, this feature will help you understand how to predictably find and photograph wildlife throughout the winter.

This topic will be part of a year-long series. How animals respond to weather is not limited to the winter. Each season holds its nuances and I think it’s high time this was a topic we discussed because understanding such things will completely change your success as a wildlife photographer.

Uncompromising quality. Workshop level education. The Art & Science of wildlife photography at your finger tips.

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