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There’s no denying that a blizzard (or a weather bomb) can slow down your birding plans by turning the world into a giant, icy marshmallow. But snow has an upside that’s undeniably magical: It acts as nature’s fingerprint powder, revealing wildlife activity with forensic clarity.

Before you put on your Sherlock cap, however, you need to learn to read the clues. Birds are a good group to get started on. They’re active after storms; they’re not afraid of fresh snow; and they’re generous enough to leave behind signs as they roost, forage, and rove.

Ready to get to the bottom of your snow-day mystery? Use these steps to work backward from any bird prints you see. 

Get a Sense of the Landscape

With so many possible species, identifying bird tracks can be devilishly tricky. So, it’s important to consider every scrap of evidence. When you find a set of tracks, take a close look at your surroundings. Are you in a forest or grassland? Is there a body of water nearby? Use your field guide or knowledge to pinpoint the species that frequent the habitat. For example, if you’re deep in a city and you find ambling, three-toed prints, you’re likely looking at urban turkey tracks, not a White-tailed Ptarmigan or Ruffed Grouse. (Sorry.)

Size Up the Overall Pattern

Fight the urge to zoom in on each step and check out the larger arrangement instead. It will tell you a lot about the bird’s style of locomotion—also known as its gait—and help you rule out some of the usual suspects. Here are some ways birds typically move through the snow.

Hopping

If the tracks are arranged in pairs, with each foot planted right next to the other, the bird was hopping. You’ll often find this behavior in species that spend a lot of time perched up in trees. Examples include goldfinches, nuthatches, chickadees, titmice, and cardinals.

Skipping

Skipping is a lot like hopping, except that the tracks in each pair will look staggered. This gait is common in Song Sparrows, American Robins, Snow Buntings, and other passerines that forage on the ground.

Walking or Running

If you see single footprints that are regularly spaced out, you’ve got a walker. Grouse, gulls, ducks, Mourning Doves, raptors, and European Starlings all tend to fall into this category. Trails left by running birds are pretty similar, but the individual marks will be farther apart. 

A note of caution: Birds are dynamic, energetic critters and might switch between different gaits as they move about the landscape. To make a positive ID, you’ll need to gather a little more proof.

(Don't stop with bird tracks. Learn to identify more than 800 North American species by their songs with Լ����Ƶ's free Bird Guide App.) 

Focus on the Shape of the Steps

A single print can unlock a wealth of information about how your ghost behaves. Try categorizing by contour to narrow down the bird by group.

Standard Tracks

In most treads, you’ll notice three toes in the front and one in the back. Perching birds like sparrows, cardinals, jays, and finches have feet as such—especially narrow, with long toes to grip slender twigs. Doves and pigeons, which spend a lot of time rambling across the ground, usually have wider footprints. And then there are herons and egrets: Their broad feet and long toes enable them to stand straight and still, even in oozing muck. Eagles and hawks also have four-toed tracks with three toes in front, but their feet are bulkier to help them grab and secure prey.

Game-Bird Tracks

Here, the hind toe is so small it can be hard to spot. In fact, it might not touch the ground at all. Grouse, pheasants, turkeys, and ptarmigans leave tracks like this, along with some shorebirds and waders.

Webbed Tracks

If there’s an outline that stretches between the three front toes, you’re looking at a duck, swan, goose, or gull. There are a few birds that have webbing between all four toes, too. Cormorants and boobies are part of that group—but the latter has the good sense to stick to warmer climes in winter.

Zygodactyl Tracks

Okay, this is one of the all-time best words. Say it slowly, with relish: zy-go-dac-tyl. The arrangement, which consists of , allows birds to scramble up trees and grip branches (or food) with more stability. Examples include owls, woodpeckers, parrots, and roadrunners.

Pack Some Study Materials

Want to get your IDs down to species? Grab a ruler to take careful measurements, and compare them to the size tables in the handy book . Or, for a more general and somewhat philosophical read, check out Paul Rezendes’ .

Search for Signs That Aren't Footprints

The next time you spot a trail of tiny mammal tracks, follow it. At the end, you might find an enormous “,” complete with the wing, tail, and talon marks of a bird of prey that swooped down and carried off its unsuspecting dinner. Without the snow, these life-and-death dramas would surely go unrecorded.