I have been this world tree. Who has not? Lately, I’ve found myself grumbling in bed just before dawn while a pair of Ratatoskrs nesting in the attic cornice right behind my sleepy head chew my house to pieces. I’ve watched them long enough to discover their convoluted route to and through a corner opening in the gutter. We had hired a wildlife expert with a long ladder to cover all such openings with steel hardware cloth to prevent the entry of rodents, but this was the one place on our tall and complicated 1920s roofline the ladder could not scale. The squirrels, naturally, get to it easily. They climb the large cypress in front of the house, jump from there to the roof over the entry, and then to the flower box under my second-floor study window. Here they might stop to gorge on the sunflower seeds at my window-suction chickadee feeder, blandly ignoring me as I tap the glass right next to their heads. After this, a run around the roof edge on the west side of the house, and a brave, hard-won (even for a squirrel) leap to the cornice. In early autumn, I wanted to discourage them from choosing this as a winter den, as just a few inches of wood and plaster were separating the Ratatoskr teeth from my bed pillow. So every morning before making coffee and strolling into my study to write about peaceful cohabitation with urban wildlife, I picked up the urban-wild-interface tool of choice, the broom handle, and beat the wall inside the closet (which abutted their attic nest) or hung out the window and reached around to pound loudly on the gutter. This would usually bring them out, but eventually they realized that all I could do with my broom was make noise and that I couldn’t hang out the window far enough to actually sweep them without falling to my death. So now the squirrels just stare at me for a moment in that wide-eyed squirrel way and then go back to chewing a bigger hole for their egress.
The squirrels in our attic and neighborhood are eastern gray squirrels, the most common urban, suburban, and city-park squirrel in most of the country. Depending on where you live and how urban-suburban your home is, you might see instead various species of native tree squirrels or ground squirrels (ground-squirrel species are typically striped or lightly spotted), most of which share common squirrelish natural history and habits. From the Mississippi westward, the eastern gray squirrel populations are nonnative, introduced accidentally when pets escaped or intentionally by misguided squirrel lovers, but in many respects, this is a moot point. Wildlife experts agree that there are too many for them to be successfully extirpated, humanely or not. Eastern gray squirrels are a permanent fixture of the urban wild.
Urban/suburban squirrels are somewhat territorial, claiming about half an acre per pair of; if you can find an identifying mark on your squirrel, like the half-missing ear on one of the squirrels that comes to my window feeder, you will discover that you have basically the same squirrels every day.
The supposition that introduced eastern gray squirrels are displacing native squirrels requires some nuance. It’s true that these gray squirrels are larger and sometimes more aggressive than other types (though if you’ve ever crossed a little Douglas squirrel or one of the other red tree species, you know that they are not to be messed with—I have seen plenty of these beautiful little squirrels chase an eastern gray away handily), but in North America, it is the destruction of woodland habitat that reduces populations of native tree squirrels. The edge habitat that results when forested areas are dismantled for the construction of human homes and other buildings (or even grassy parks) is suitable for the gray squirrels, and they move in readily. In the UK, where the habitat of the smaller red tree squirrel overlaps more intensely with that of the introduced gray squirrel, it does appear that the larger gray squirrels are forcing the natives out and threatening their populations. But here in North America, it is human activity, far more than the nature of the squirrel species, that controls squirrel presence and absence.
Urban squirrels are not particularly careful about hiding their nesting places, or dreys, and will construct them throughout the year for different purposes. In the early spring, they find a cozy place safely above the reach of ground-dwelling predators to birth and raise their young. Kits of most squirrel species are nursed and cared for by the mother for three months, a long time for any mammal, let alone a rodent. Male and female squirrels look alike, but in the right season, when females stand on their haunches, we can see the enlarged nipples, signs of new motherhood. We rarely glimpse the young until they are nearly full-size, but they can be distinguished by their relative clumsiness, their caution in navigating trees, and their skimpy tails, not nearly as full and bushy as the adults’. In the winter, squirrels find warm places to den up. Either of these dreys—nursery or winter shelter—might be one of the round balls of leaves we see in trees, easy to spot in winter when the limbs are bare. Crow nests are large, dark presences in the trees too, but they are made almost entirely of sticks, and not covered with a mounded roof, as squirrel dreys are, though squirrels may use old crow nests as bases for their own. There is a small entrance, a hole at the top of the drey.
Leaves are a common drey-building material, but they might also include found mosses, fur, and other soft things. Mysterious bits of shredded newspaper were showing up on our drive one autumn month. The Seattle rain glued the paper scraps to the cement, and we had to scrape them off with our fingernails. Soon enough we discovered a squirrel drey in the neighbor’s fir, with Seattle Times confetti tucked among the leaves. Squirrels will also nest in woodpecker cavities or in nest boxes put out by humans for larger birds—woodpeckers or owls or wood ducks. The recommended dimensions for a squirrel box and a flicker box are exactly the same (would-be housers of birds need to take this into account).
But why would a squirrel bother with any of this when there are roofline cornices to be had? In urban and suburban neighborhoods, human houses are the favored squirrel shelter. Since there were no electrical wires where the squirrels were nesting in our attic, and since they were unfazed by my broom-wielding, we decided to wait it out. Occasionally, squirrels will take up permanent residence in human homes, but more typically, their presence is seasonal, and if you bide your time, they move out on their own—when the weather is warmer, if they were denning, or after the young have grown, if they were nesting. This is a good time to clean the area out, if you can, and block the entrance route from future rodentia. Lethal control is never permanently effective. There are lots of squirrels (and rats), and if you kill the ones that are present, more will eventually move in. The smell of urine from the previous residents will attract others. The best method is to wait till the squirrels are gone or to live-trap them, and while they are out, effect structural changes to prevent reentry, making sure there are no young left inside. (Not only will they die cruelly of starvation, but dead squirrels in the wall will smell really bad for a couple of months. On this, I speak from sad experience.) Besides the annoyance issue, frayed electrical wires and messed-up insulation are the main concerns with squirrels. Squirrel waste and the squirrels themselves carry bacteria that could theoretically harm humans, but disease transmission, including rabies, between squirrel and human is almost nonexistent.
The squirrels among us are far and away the most ubiquitous observable urban-wild mammals. Rats are present in numbers, but they are secretive and nocturnal. We can observe squirrels almost whenever we want to. Because they are utterly commonplace, accessibly diurnal, and in many places notoriously nonnative, we often consider squirrels as being pretty much beneath our attention. This was my long-standing urban squirrel attitude. While I would go out of my way to observe and study woodland squirrels (both Douglas squirrels and northern flying squirrels can be found in Seattle’s forested parks), I knew very little about the squirrels that lived under my nose. But their presence is in many ways a wonder. Here are wild mammals, coming in close, allowing us to watch, to sketch, to learn something through their general behavior about the less-observable squirrel species, to pause and consider at length our shared mammalian biologies, our twined urban ecologies. In its commonness, the squirrel offers an opportunity
that is rare.
Here is something I discovered about squirrels while immersing myself in the urban wilds for this project, something I didn’t know before: squirrels are beautiful. I always knew that they were bothersome but cute. Classically bright-eyed and bushy-tailed. But it wasn’t until I sat on my bum for hours to observe and draw and ill-advisedly tame a few that I noticed their honest animal beauty. Each wide eye is rimmed with golden-brown crescent moons, one above, one below. The fur is ticked, shades of gold, red, gray, black, mingling around a pure white-gray belly. The tail is layered, with soft-edged stripes of these same colors. (Some populations are golden-red with light pumpkin-colored bellies, some are solid black or solid white. Communities build tourist billing around such squirrels, and protect them exuberantly. All are different color morphs of the same species—eastern gray squirrel.) Their feet are softly furred, long and thin, elegant. In more forested parks where they feel less exposed and are calmer, squirrels sometimes become less twitchy in their habits, and their agility starts to seem more graceful than jumpy. I’m not saying squirrels aren’t a nuisance and nine kinds of trouble. I’m saying that no matter what else they are, it is possible to step back from our shared squirrel prejudice—whether it reduces them to fluffy cuteness or mere annoyance—and see them from the outside, as wild, graceful, and lovely.
Squirrel Tracks and Sign
Urban squirrel sign is subtle. They defecate randomly, so their scats don’t accumulate, and you rarely spot them except in a small space where a squirrel has spent a lot of time, like an attic or a toolshed that happens to hold the birdseed supply. And squirrels are too light (and light on their feet) to make tracks on most urban substrates. The exception is a snowy day, when you’ll see their bounding trails, back-foot tracks ahead of the front, or their droppings, bright black against the white, sometimes absorbing snow fluid until they burst into circles of red-brown.
But there are other signs that indicate squirrel activity. Look for the debarking of branches, where strips of the outer cambium have been peeled away for food or, possibly, to line the drey, if the tree is a soft-barked cedar. You can actually see marks from the incisors at the edges of the peeled areas. If the scraped patches are close to the bottom of the tree, the creature that made them is likely to have been a vole or a pocket gopher, and wide peeled patches low on the tree may indicate the presence of a porcupine. Squirrels like to de-bark at a height where they can worry less about predators—six or eight feet up, and higher.
Look for clippings. It is astonishing how often we walk past a tree surrounded by tips of its own branches without stopping to consider how this came about. Squirrels and chipmunks can’t support themselves on the slenderest outer limbs of a tree, but that is where the freshest buds for feeding and the plumpest cones for winter caching often lie. The squirrel will clip the end of the branch off and let it fall to the ground—sometimes dozens of them—then descend to dine on terra firma, or carry the tips one by one back up the tree to eat on a protected branch near the trunk. Watch also for empty hazelnuts and mast, the squirrel’s favorite autumn harvest. Birds like jays and crows will hack nuts open cleanly with their bills; nutshells left by squirrels will have teeth marks. (After larger birds or squirrels open the nuts and eat most of what’s inside, chickadees will come and clean up anything left in the shell corners.)
Above is a comparison of deer mouse, Norway rat, and eastern gray squirrel scats, showing their relative size. Other species of mouse, squirrel, and rat scats are similar. Accumulations are found in households where any of these rodents have been attracted by food and shelter that is relatively undisturbed by humans—basements and sheds are perfect. The size of the droppings will let you know who has been visiting. Rat scats are decidedly larger than squirrels’, vary more in shape, and show more light-colored fiber. But in spite of anti-rat sentiment, rats—and their leavings—are not “dirtier” than these other rodents.
Aesthetically, at least, it is difficult for most people to find anything to appreciate about rats, the urban squirrel’s nocturnal counterpart. The rat body is a classic teardrop shape, wider at the back end and narrowing to a point at the snout. There is not much delineation at the neck or the nose. The eyes are black and not large, though not as small and beady as we imagine them. The fur is short, and brown, gray, or almost black, depending on the species and the individual, and the feet are much smaller than a squirrel’s. Even a member of the climbing-rat species does not have the long toes and accompanying aerial agility of a tree squirrel. But it is the slender rope of the rat tail (isn’t it?) that somehow encompasses all of our psychological distaste for the rat—pale, scaly, hairless, dragging unseen through the gutters of our homes and minds.
The persistent belief that there is one rat per person in urban places is based on a dubious study from rural England undertaken in 1907. And though the statistic is constantly repeated by public-health experts and rat exterminators, for modern cities, it is entirely untrue. How many rats are there really? Well, we don’t know; rats are quiet, wary, and nocturnal, and we have no good way to count them. But in the United States, the number is likely to be far fewer than one per person—more like one per family. When I asked a rat-control professional about the one-per-person figure on his website, he copped to knowing it was an exaggeration. “The more rats people think there are, the more freaked out they are, and the more business I get.”
Even so, if you live in a city, there are rats living with you, whether you see them or not. And while there are several species of native rat in this country, the human commensals—the two species of city rats—are introduced. The smaller is the roof rat, Rattus rattus, a good climber, found mainly in the southern states and California. The most common is the brown rat, Rattus norvegicus (also called the Norway rat, subway rat, sewer rat, alley rat, house rat, wharf rat, gray rat, Norwegian rat, or common rat), which, in spite of its scientific name, originated in Manchuria. They spread to Europe by foot and their rat wits, and sailed (along with pigeons) to North America on the ships that brought the colonial settlers in the mid-1700s. It is typical for people who find a fat brown rat in the basement (cornered, frightened, and therefore aggressive) to claim it is evil and “big as a cat.” But rats rarely grow to weigh a full pound, and from tip to tail, an average one measures about ten inches. And unless cornered, they are typically gentle and will avoid humans.
Rat Tails
Of all tails possessed by mammalian species on the face of the entire earth, rat tails inspire the most revulsion. “Their icky tails” is often given as a reason that people hate rats themselves. Even people who want to like rats—people who respect their intelligence and playfulness and who might consider a rat as a pet for their children—often lament that they just can’t get past the ugly tail. What if rats had fluffy tails like squirrels? Would we like them better? In an effort to understand, I carried out an unscientific study, interviewing fifty friends and online contacts to see if I could discern some psychological thread in the complex labyrinth of rat perceptions. While a very few claimed to be unbothered by the tails (no one confessed to an outright fondness for the things), most of the responses to my little study could be grouped into four general trends:
1. We hate rat tails because the tails themselves are ugly. Rat tails are not hairless, but they are quite bare, and the hair that does grow on them is stiff and hard. The tail skin is sometimes dry and flaky, which makes the tails appear scabby and diseased. Rat tails are the sorts of things we are taught from a young age not to touch, for fear of catching a dreaded something. Opossum tails inspire the same reaction.
2. We hate rat tails because they are snakelike. A fearful response to snakes is so universally common that many believe it must be an inborn evolutionary protection mechanism. Recent work by researchers at Carnegie Mellon, however, suggests that while humans are not born with an innate fear of snakes (or spiders, for that matter), we do have what’s called an evolutionary bias that predisposes us to quickly notic
e things that have posed threats throughout human history (the squiggling thing at the edge of one’s peripheral vision) and associate these with fear via cues from the environment—say, your mom shrieking or someone yanking you away. It appears that a rat tail triggers this response, dragged behind the animal, looking as if it has its own unpredictable snaky life.
3. We hate rat tails because, as such things go, they are too big. Hairless mouse tails are attached to tiny little mice. Rat tails cross a kind of psychological threshold. My friend Clare tells me that rats give her the shivers, in part because of the “long, scaly, bony tail that drags along the ground like some forgotten appendage.” Mice are different. “Field mice—in fact, all mice—are cute,” Clare says. “Tiny bodies, big round ears, even their weenie hairless tails are cute.” For Clare and so many others, the tail issue comes down to size. Small = cute. Thick and ropey = disgusting.
4. We hate rat tails because they are attached to rats. This is a tricky one, a chicken-egg problem that is difficult to untangle. The bushy-tailed wood rat, or packrat, looks much like an Old World rat except for its tail, which is furry. Not as fluffy as a squirrel’s, but far furrier than urban rats’ tails. Most of us have not encountered these fluffier-tailed rural rats and so have no opinion about them, There is no good way to tease out revulsion of rats from revulsion of rat tails. One way or another, our conflicted or outright disgusted feelings toward rats are tangled up with their ratty tails.
The Urban Bestiary Page 10