Santiago is tracking a deer. He has been tracking deer relentlessly for weeks, but we’ve not seen any since Christmas Day, when he flushed eight of them–with their flashing, chorus-girl rear ends–from hiding behind an apartment garage. We are trotting beside a chain link fence at the edge of a park. Our footfalls are obliterating the hooved prints in the snow which constitute the trail that we are following. Santiago does not slow as he pulls me underneath a fallen maple tree lying across a tangle of shrubs. Its papery seeds brush my back as I crouch and run, seeing deer scat, now, beneath my boot.

Last week, I took Santi to a conservation meeting. Before leaving him in the car with a snack and a blanket, I let him run along a Mississippi River bluff in the dark of evening. He repeatedly burrowed his nose down into the snow, straining at the leash and begging to run off into the yards of neighboring river-dwellers or down the steep bank to the water. When we got home later that night, I had to wash the musky stench of deer urine off his snout.

Though we stop and stand very still beside the fence, gazing with held breath into the uniformity of the dun-gray trees against the white-gray sky, we do not see a deer. So we move on, and the day is full of wonders. Pink paddleboats are docked on the beach and dressed in snowdrifts under shifting, silver clouds. The squeals of children croon over the woods from a steep hill so slickened by their sleds that it is icy black mud in the middle. At the edge of a frozen marsh, someone has scattered birdseed over the toppled remains of a snowman, and, on a bench, two sprays of browning evergreens with painted pine cones and bright red bows have been left where a plaque spells out two names, “United in Marriage.”

Santiago watches a fisherman. The man has not yet reached the lake. He is dressed in dusky, winter finery: a padded blue coat and pants to match, the latter swishing softly as he walks across the snow. His hood is up, changing the shape of his head, and bulky boots and mittens further distort his silhouette. He moves slowly, deliberately. There is something prehistoric about his gait. An eight-foot rope is affixed to his waist, and he is hauling behind himself a plastic sled. It is loaded with the five-gallon bucket that will serve as his chair, along with the rest of his ice-fishing gear. Santiago keeps his eyes on the man, walking sideways, tail alert, a bark at the ready in his throat.

I do not know what my dog’s memories are. I know that when we encounter boys playing hockey on the rink at nightfall, he watches them under the stadium lights, pulling on the leash until we are out of their range. I know that he barks nervously at men swinging golf clubs on watered, green courses. I know that a park statue of a mustachioed man holding an axe once caused him to turn and run, looking over his shoulder, bleating.

We walk for a long time. We leave the clamor of the children behind, and the zip and rumble of snowmobiles on the lake. We walk beside birch trees. A bald eagle circles over a cemetery on a hill, next to a little, white chapel. I think about the juvenile eagle I saw just a few nights earlier, on Valentine’s Day, when the wind was cold and Santiago was nosing at the snow along the path and I wanted to go home. The bird emerged among the reaching fingertips of the trees–startlingly close and sudden–his wings mottled like marble or confetti, and huge, flapping in the gawky way of an adolescent, loping across the sky. It was two years since the day that I’d heard about the death of my cousin. That Valentine’s Day, I had sat in my car and seen in the bright blue sky above a traffic light my first bald eagle of the spring. I had bent my neck to watch him glide over rooftops wet with melting snow, flying toward a lake.

A minivan passes, leaving the park. A woman with brown curls that frame a pale, round face shouts from the passenger window, “I like your dog!” We have been walking uphill and I am warm with exertion. I take off my hat and gloves and stuff them into the bag that is slung across my chest. Chickadees call. A jogger approaches from behind us, a man in black spandex. “Our side,” I whisper to Santiago, and he minds for a moment, then catches a scent and wanders to the left snowbank for a sniff. “Hi, pup,” the man says, cupping a friendly palm to Santi’s snout without breaking his stride. Santi wags his tail.

There is a dog on the path ahead of us. She is made of cotton balls and nutmeg. About a year old, not quite full grown, she is walking with a woman in a powder blue hat who tugs on the leash each time the pup turns to look at Santi. He has not yet seen the the dog but is noting her aroma on the path. The woman stills her, forcing the canine to sit silently in a snowbank and witness our long advance. The cotton balls quiver. The brown eyes stare. Santiago sees her and begins to bark and tug. What might have been a one-and-a-half second passing is now an extended conflagration of dogs, their curiosity and anxiety sparked into a blaze of confused leashes and stretching muzzles.

“On by,” I say gently to Santiago as we skitter over a patch of cracking ice.

“All done,” I say.

I do not know the origin of my dog’s fears, which include basements and being left in the rain. I do not know the stories that he tells himself. I know that he likes pretty women and men in trucks and children. His adoption papers say that he ran away from home three times, and I’ve watched him attempt to board a city bus more times than that. I know that when the vet explained that the hairless patch of pink skin on Santi’s leg was caused by confinement in a space so small that he could not move, I burst into sobs so vehement that they embarrassed me. I know that big dogs make him bark louder and longer. I think that in his mind, he is small.

We walk for more than ninety minutes, passing through a tunnel bright with graffiti and flooded with ice. Santiago hunts for mice and rabbits in the tall grass and crusty snow around a hillside sewer cover. We can see traffic from here. There are fences around the houses beside the trail.

The puppy is off leash when we return. She stands for an instant, motionless on the path, the woman in the powder blue hat many feet behind her, shouting something. Santiago pauses, too, assessing the scene, then lunges to the end of his leash, whooping his baritone woof. The cotton balls surge: a thousand tufts of fluff each wagging independently in the winter wind. The puppy races toward us.

“It’s all right,” I call to the woman. “He’s friendly.”

The dogs meet at their snouts, then sniff, face to belly. And then they play: bouncing away from each other, dashing forward, hooting and hollering, ramming into snowbanks, chasing tail.

That’s all they wanted.

Before we go home, Santiago takes me through the woods. The sledders have gone quiet. Lunch hour has long since passed. Santi stops at the pond, considering. The snow here is packed hard by boots and the trees are young. They are slim and straight. On the ground, here and there, are weathered poplar leaves and broken birch limbs. Santiago is leading me up a hill. The path is narrow, trod by only a few feet. I realize as we climb that several months ago, when the evenings had become short and smelled of wood smoke, and the very latest berries of the season still clung to the trees, when we looked forward to the romance of pumpkins and Thanksgiving and the first snowfall, we stood at the bottom of this slope and stared into the uniformity of dun-gray trees against the dirt-gray earth, the sun sinking a cold gold behind us, and saw at last the magnificent buck that we had been tracking, up here, where we are now, watching us with his calm eyes, the crown of his rack like a faintly glinting, holy thing.

When we go to bed, Santiago dreams. His muffled barks sound like soap bubbles popping. His legs twitch. His mouth parts. I do not know what he sees. Perhaps he is wrestling with a dog made of cotton balls. Perhaps, freed at last from the tether of my leash, he has chased and seized a buck between his jaws. Perhaps he dines on venison. Perhaps he glides above treetops and steeples like an eagle among shifting, silver clouds.

Perhaps, at last, he is large.