I once spent five days on an island off the coast of New Zealand, a refuge for some of the rarest bird species on the planet. The island was alive with amazing birds all day, but the one I most longed to see was active at night, the spotted kiwi.

For four nights I crept along the island trails as silently as possible hoping to catch a glimpse of one, to no avail. On my final night on the island a biologist suggested that I make a little noise as I walked; perhaps I would startle a kiwi into revealing its location.

That night I walked along briskly, humming a cheerful little kiwi questing song. I had not gone half a mile when I heard a rustling. In my flashlight beam I saw what looked like an ambulatory eggplant wearing a brown fur coat. The little spotted kiwi gave a couple of bemused bows, shuffled a little closer to me, looked me over, and then resumed foraging.

I watched until the bird disappeared into the undergrowth, and then, mission accomplished, I turned back toward the bunkhouse. I soon heard another rustling. This second kiwi was so close I might have touched it. A third kiwi betrayed its location as I clomped over a boardwalk.

I relate this story to support a theory I have about a local mammal, the gray fox. A pair of these foxes include my yard in their territory. Gray foxes may be the most beautiful dogs in the world, with crisp black and white markings on their faces, alert ears, and thick, long, fur, but the sounds they make are not lovely in the least -- raspy, high-decibel barks. I call them barks because that is the noise dogs are supposed to make, but they hardly seem to be of canine origin.

According to the popular fox literature, foxes vocalize mainly during the early winter mating season, yet my foxes have been barking right through spring, summer and fall. During the summer I heard their barks around the clock as they searched for food for their kits. Perhaps these barks help the pair keep track of each other, though I can think of no reason why this would be important. I have often watched one fox while the other barked in the distance. The watched fox continued its activities, so the bark is apparently not an urgent summons. Do these barks let the kits know where their parents are? I have only seen the two adult foxes so I don’t believe any kits remain in this home range. Still they bark.

So, how to explain it? How can it be advantageous to a hunter to create such a din? Here is where my kiwi stalking experience comes in; if mice, like kiwis, make very little noise most of the time, it might behoove the stalker to startle them into moving. I hypothesize that, as these foxes trip lightly through the woods on their dainty paws, mice, voles and shrews go about their business in near silence.

I suspect that an ear-splitting roar at close range would cause even the calmest mouse to jump out of its furry pants. Once a mouse betrays its location to an alert predator, the predator has an edge.

I have wondered the same thing about the barred owls in my neighborhood; they make noise year-round. Why do they bother with silent flight if they create a ruckus when they’ve landed? Could it be that the silent flight allows a stealthy arrival, while the piercing shrieks startle their prey into moving?

I set out one night last week to look for Fretful the porcupine at the den site he used last winter. I found him, instead, at a ledgy site much closer to my home. There I also found an abundance of tiny mammal tracks. Since the population of small mammals in my neighborhood is generally depressed this year, I was surprised to see so many. Could this be sign of a boulder habitat specialist, like the long-tailed shrew or the rock vole? If so, would such small mammals be as willing as their kin to reveal themselves for a reward of sunflower seeds? The next night I returned. I brought apples and acorns for the porcupine and sunflower seeds for the mystery mammals. The night was cold, clear, still, and very dark. I settled in to listen and wait, and lapsed into a state of deep relaxation (sleep?). I did not hear any crunching footsteps of an approaching porcupine. The tiny mammals remained under the rocks. Eventually, I did hear the barks of a gray fox, three barks in a row, not too far away. The next series of barks cut the distance between us in half. Did this fox also know of the small mammal bonanza among these rocks? As I waited and listened for the next barks, I began to doze again. I lurched from the depths of this relaxed condition when the fox’s bark sounded from somewhere within 150 feet. I did not leave any articles of clothing behind when I jumped, but I nearly did, and I knew the fox was in the neighborhood.

I am not wed to my theory. These foxes could be barking for a variety of reasons. Maybe they enjoy the noise. What do you think? I’ll bet that even if they don’t bark while hunting, they occasionally dislodge hidden prey with their clamor.

The mystery voles or shrews did not reveal themselves to me that night, and Fretful the porcupine never showed up either; I did, however, discover him when I got home. Fretful had gone to my house looking for me, his first visit since the summer.

Patti Smith is a naturalist at the Bonnyvale Environmental Education Center. The View From Heifer Hill, a feature on the nature of our region, appears in this space the first Saturday of each month. Patti welcomes your feedback at patti@beec.org.