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Posts Tagged ‘human-wildlife conflict’

The British may have lost North America but their native house sparrows have successfully colonized the continent.

The British lost North America but English house sparrows have colonized the continent.

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It seems to happen once each century. In 1775 the Redcoats showed up in Boston, the Beatles made a big splash about 200 years later in 1964, and in the sweet-spot in-between the House Sparrows (Passer domestics) arrived.
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It’s difficult to believe, given current controversies and political grandstanding, but for a long time America had a very open-door immigration policy that allowed almost anyone—human and non-human—hassle-free entry. For example, no one batted an eye when my paternal ancestors washed up here after being kicked out of Scotland during the Highland Clearance to make room for sheep… but I digress. In the 1850s, when Brooklyn Institute Director Nicholas Pike purchased 8 pairs of house sparrows from England he didn’t have to sneak the birds past a Customs agent—the Animal and Plant Health Inspection Service (APHIS) hadn’t been created yet and wouldn’t be for over 100 years. Nor did Pike need permission from the New York Department of Environmental Conservation to release the birds. It didn’t exist.
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Introducing these Old World sparrows to North America was not done on a whim. Some sources suggest the birds were imported to control a serious canker-worm (Alsophila pometaria or Paleacrita vernata) infestation threatening New York City’s trees—a somewhat misguided notion since house sparrows are granivores (seed-eaters), not insectivores, although they do feed insects to their nestlings.  Pike reportedly paid $200 for the pairs’ passage across the Atlantic, which may not sound like much but according to one relative-value calculator it’s equivalent to $5,000 today.
.feeding the sparrows
Like many immigrants before them those first settlers didn’t do all that well in their new home. Not dissuaded, Pike purchased another 25 pairs the following year and released them along the East River. This cohort proved hardier, or perhaps more adaptable. Another 100 pairs were ordered in 1853 and released at the Greenwood Cemetery, Central Park, Union Square Park, and Madison Square Park. Americans have a history of Anglophilia so it should come as no surprise that soon the former colonies were all a-twitter about these chatty, cheerfully social birds.
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male house sparrow by Eric Bégin, CCLHouse sparrows aren’t closely related to native North American sparrows and you can see it in their physique—they’re a bit heavier, with a deeper chest, a more rounded head, shorter tail, and a less delicate bill. Six inches (15 cm) long from beak to tail-tip, and weighing in at about 1.4 oz (40 g), the male house sparrow cuts a dashing but not flashy figure; he’s British, don’t forget, and all business. Bright blues, greens, and yellows are not his cup of tea; rather, he wears a neutral palette of black, gray, and chestnut, with a touch of white to sharpen up the entire female house sparrow2ensemble. Female fashion preferences are appropriately tweedy: tawny-brown with darker striping on top, oatmeal-tan or gray below. More Anthony Hopkins and Emma Thompson than David Bowie and Amy Winehouse, nonetheless, house sparrows were a trending novelty that went viral.
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Entrepreneurs recognized a market opportunity and became breeders.  Citizens in Maine, Connecticut, Rhode Island, and Pennsylvania all followed Pike’s lead, and by 1870 this pioneering species had spread south to Texas, north to Montreal, and past the Mississippi River to Iowa. A West Coast population was established with releases in California (1871-1872) and Utah (1873-1874), and in the subsequent decade house sparrows expanded their range from less than 1,200 mi2 to over 500,000 mi2. By the turn of the 20th century the space between eastern and western fronts had nearly filled.
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Why have house sparrows thrived while other species—including some natives—have failed? Here are the keys to making it in America:
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Get lucky.  House sparrows couldn’t have wished for better timing to facilitate their successful acclimation. Steam and internal combustion engines were coming on strong but horses and cattle were still the primary means of facilitated transportation. Working herbivores need more calories than grass and hay alone can provide so corn, barley, oats, wheat, and rice are common additions to the diet. Hoof-stock “exhaust” has a fair amount of undigested “fuel” and resilient city sparrows weren’t picky about where they got their vittles. Additionally, urbanites raised livestock and poultry and a small bird could easily slip in and out of pens and stables to pinch a bite or two. Enterprising sparrows even hitched rides on those new-fangled locomotives and their boxcars filled with grain.
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Grow up fast, breed early and often.  House sparrows eggs hatch after 10-16 days of incubation, nestlings fledge at 14-15 days old, are independent 7-10 days later. One study suggests they may reach sexual maturity as early as 4 months of age—time to find a mate and get busy! Females produce 2-5 clutches of 3-7 chicks per breeding season; that’s an average of 20 chicks per season, per breeding pair. Do the math and there’s your answer.
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Stand up for yourself and your kin.  House sparrows will form loose nesting colonies, are strongly territorial, and will aggressively defend nest sites and feeders. They’ll attack both intruders and potential intruders, and have been known to destroy the eggs and nestlings of competitor species.
. Be smart, adaptable, and adventurous.  Many bird species follow a strict set of guidelines when it comes to choosing where to raise a family.  Sparrows, on the other hand, sparrow nest by gingiber, CCL are willing to at least consider nearly any property when scouting for real estate. You’ll find them nesting in a wide range of locations—nest boxes and tree cavities, of course, but also signs, architectural features, drain pipes, dryer vents, and anywhere else that offers a large enough entrance.  When a potential nesting site has been identified they’ll use every means at their disposal to make it work.  They can even learn how to trip automated door sensors to access food and shelter from the elements and predators. When young house sparrows are old enough to leave the nest they’ll readily disperse 5 miles or more to find new feeding and nesting areas and quickly learn how to claim and exploit available resources.
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Have friends in high places. If you’re a wild thing, having H. sapiens on your side is the equivalent of a royal patronage. In the mid-19th century people trapped house sparrows from one place and released them into new territory cleared of predators and outfitted with nesting boxes.  That, my friends, is what’s called “choosing sides.” Is it any wonder house sparrows are now found in all 48 contiguous states and Hawaii’i (where they were introduced from New Zealand in 1871)? The kindness of human strangers has also allowed P. domesticus to claim much of Canada, all of Central America, most of South America, southern Africa, and eastern Australia.
dark green = natural range light green = introduced range

dark green = natural range     light green = introduced range

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I’m sure you can guess how this story goes, though. It’s been played out countless times in the media—print, broadcast, and social.  First they love you, then they love to hate you.  Americans adore a winner but as any reality TV star can attest, get too successful and fans will take equal pleasure in watching, sometimes facilitating, your fall from grace.
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Even as the house sparrow fad continued to grow, some conservation-minded folk had begun to notice the immigrants were not assimilating as hoped, or following local customs and expectations. Before long, civic leaders had deemed house sparrow nests “unsightly.” Their droppings were blamed for “besmirched” buildings and sidewalks.  They were tagged as thieves who pilfered valuable grain from honest, hard-working farmers. Worse yet, the foreigners were observed being downright inhospitable to the native avian community, including valuable insect-eaters. The nerve of those ungrateful little upstarts!!
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sparrow trap (Albert F. Siepert, Project Gutenberg License)Guides for trapping, shooting, and poisoning the birds were distributed free of charge. By 1883, state legislators in Indiana had declared the house sparrow an outlaw who should be killed on sight. Five years later, Illinois and Michigan had established a small bounty on “English” sparrows and children scrambled to exchange dead birds for cash to buy candy.
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Never mind the fact that human development was having at least as great an impact on native bird species as the house sparrow we had intentionally loosed upon the landscape. Forget that the effects of trapping and poisoning are rarely limited to the intended target species. Ignore the lack of conservation legislation that allowed “market hunting” to bring dozens of wild bird populations to the brink of extinction. The public was frightened and angry about the changes in their communities wrought by industrialization and human migration. Scapegoats were needed to pay the piper for society’s sins and transgressions.
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Many individual house sparrow were killed but despite the all-in extermination effort the species continued to thrive. While no longer hunted for bounties in the US., the bad PR stuck like glue—to this day they are generally resented or reviled. Unlike migratory species house sparrows are not protected in the U.S. and, in fact, the population has declined somewhat.
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save-sparrowFollowing the tried and true media script, the house sparrow is experiencing a rebound in popularity, at least in its native range. This is due to precipitous population declines in England, where this native species has been “red-listed,” Europe, Scandinavia, and India. The problem seems to be a lack of available food for their young—nestlings need the higher level of protein insects provide, only later changing to a grain-based diet. As Rachel Carson pointed out decades ago, our pesticide arms race takes a toll on many of the creatures we enjoy having around. Over the past 10-15 years, “Save Sparrows” campaigns have encouraged home-owners to decrease or eliminate insecticide use, choosing insect-attracting plants, and intentionally increasing nesting sites.
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I’ve yet to see anything in the scientific literature proposing North American as a possible source of imported house sparrows to repopulate their original range but there’s a nice full-circle appeal to that storyline.  Maybe you can go home again.
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love-earthThis blog, like so many activities that foster support and appreciation of the natural world, is a labor of love. If you’ve enjoyed learning about the creatures who share our built environment, consider becoming an NDN Benefactor with a donation of any amount you’re inspired to give. If you’d like to find a little Next-Door Nature surprise in your inbox just click the Subscribe!  button in the upper right-hand corner of this page and receive notifications of new posts!
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© 2015 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work  but please ask). Thanks to these photographers for making their work available through a Creative Commons license (CCL) or Project Guttenberg License (PGL) (from top to bottom): Martha de Jong-Lantink, CCL (birds on a branch); Harper & Brothers, PGL (feeding the sparrows); Eric Bégin, CCL (male HOSP); Phil McIver, CCL (female HOSP); gingiber, CCL (HOSP nest); Cactus26, CCL (HOSP distribution map); Albert F. Siepert, PGL (sparrow trap).

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common brushtail possum (Photo: David Midgley, Creative Commons license)

Common brushtail possums know how to work the cute (Photo: David Midgley, Creative Commons license)

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Consider, if you will, the sartorial importance of tail attire.  To bare, or not to bare… that is the question.  The answer might seem to be of little consequence, but for marsupials living in cities and suburbs some strategically placed fur can make all the difference.

That’s because naked tails make people nervous. I blame this bias on the Black Death. Of course, now we know the true culprit in that famous pandemic of 1347 was not the rat, but the infected fleas that hitched a ride on those hapless rodents. Since standards of human hygiene at the time were rather… haphazard, shall we say, there were plenty of opportunities for the insects to hop onto a handy human. We may not remember why rodents make us uneasy but the bias remains to this day.

How else do you square our acceptance and even advocacy of squirrels and chipmunks, for example, with our abhorrence of rats and mice? As Carrie Bradshaw of Sex and the City fame so wisely observed, “A squirrel is just a rat with a cuter outfit.” Clothes make the man and the mammal.

The same could be said of the common brushtail possum (Trichosurus vulpecula) and its cousin the Virginia opossum (Didelphis virginiana). Both are omnivorous marsupials of similar size and weight. However, the former has a hirsute terminus while the latter’s prehensile appendage is as furless as a snake. Brushtails are the source of much frustration among Aussie homeowners who, nonetheless, demonstrate great fondness for this plush-toy wannabe. The North American model does not enjoy a similar degree of affection from its human neighbors (to put it mildly).

Is this inequity mere coincidence? I think not—if you ask me it’s blatant bare-tail bigotry!

Personally, I find the adult Virginia opossum to be a handsome creature and their young ones winsome and endearing.  But—let’s face it—we only have one marsupial here in the U.S., so there’s no competition for best in show.

It’s a different story in Australia, where possums* and the closely related gliders account for approximately 30 of the continent’s 140 marsupial species. Brushtails are attractive animals by any aesthetic standard, with thick, luxurious fur that ranges in color from silver-gray to cream, brown, black, and even red, depending on the subspecies.

As the name implies, the common brushtail is a familiar resident along much of coastal Australia including the major metropolitan areas such as Sydney, Melbourne, Brisbane, and Perth. Suited to a wide variety of habitats, from rainforests to semiarid regions, this semi-arboreal (tree-dwelling) possum has adapted readily to urban life, trading traditional tree cavities for a home under the eaves.

brushtail mother and child (Photo: mugley, Creative Commons license)Brushtails can breed at any time during the year, but there are two peak seasons—from September to November (southern hemisphere spring) and from March to May (Australian autumn). Following a 16-18 day gestation, the female gives birth to a single blind and extremely underdeveloped child who scrambles unaided up to her pouch. Once inside, it will attach to a teat and remain there for another four or five months, after which it will either stay home at the den while Mom goes out to forage or ride along on her back, sharing any groceries she finds while learning what and where to eat. Male possums are not involved in child-rearing.

Human or non-human—if you want to succeed in the urban jungle, it sure doesn’t hurt to have a pretty face. Brushtails have large ears perched on a rounded head, a pink nose and dark liquid eyes… and they don’t seem at all shy about working their assets to full advantage. They may have learned a thing or two from eastern gray squirrels (Sciurus carolinensis), introduced to Australia sometime between 1900 and the 1930s—there’s just something about watching a furry creature nosh while holding the treat with two hands that people find irresistible, apparently, because hand-feeding fruit treats is a popular past-time.

attic brushtail (Photo: play4smee, Creative Commons license)There’s a down side to this Down Under hospitality, though. With warm, dry sleeping berths and plenty to eat, brushtails haven’t found it necessary to step lightly on the Earth… or in the attic either.  Their heavy-footed nocturnal comings and goings and loud vocalizations are responsible for plenty of sleepless nights and lost tempers. Brushtails often wake the neighborhood dogs as they wander through the neighborhood via utility poles and fencing, creating the same kind of hard feelings directed at Virginia opossums on the other side of the globe, for the exact same reason.

When not snacking on handouts from the produce section they will munch on magnolias, roses, and other selections from the flower garden as well as on eucalyptus and other trees—Aussies do not consider this one of the brushtail’s more appealing qualities. And, like their northern hemisphere kin, brushtails will dumpster dive and help themselves to the back porch pet food smorgasbord, resulting in much hair-pulling and teeth-gnashing by Homo sapiens.

Yet, somehow, brushtails seem largely immune to the vilification of their less charismatic cousins. To the cute (and furry-tailed) go the spoils, I guess—it’s an all too familiar tail and decidedly unjust. But as my mother (and probably yours too) always said, “Who told you life is fair?”

One thing’s for sure, it wasn’t a ‘possum.

[This one is for Barb at Passionate About Pets and People. Thanks for your support and encouragement!]

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* Although both are marsupials, it is commonly accepted that the Americas have opossums (colloquially referred to as ‘possums) while Australia has possums. Yes, it is confusing. No, I don’t know why or how this came to be. Even in the 21st Century there remain great unsolved mysteries.

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© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work. Just ask.). Thanks to these photographers for making their work available through a Creative Commons license: David Midgley (brushtail eating an orange); mugley (mother and baby); and play4smee (attic brushtail).

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Urban living for Sadie the Squirrel by Tom Fischer Photography, Creative Content license

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Add another accomplishment to my resume as official wildlife guru and animal-vehicle biologist for NPR’s Car Talk—the 14th most popular radio show on the U.S. airwaves and the 6th most popular if you exclude shows that feature a some kind of shock-jock (and that, I’m sure hosts Tom and Ray Magliozzi would agree, is pretty shocking).

No April fooling. In addition to answering questions for their Wildlife & Your Car FAQ page and helping a Wyoming caller understand why horses consider the hood of her car an appropriate alternative to chewing gum, I’m now a guest blogger on the site as well.

Wrangers Escort Gremlins shares some listener tips for preventing and humanely discouraging packrats and other rodents from turning your engine compartment into an apartment and an ingenious method for convincing snakes (pet pythons as well as serpent strangers) to vacate the interior of your preferred form of motorized transportation. Why wait? Click and Clack on over to the blog site before you find yourself staring into a pair of beady eyes or on the receiving end of a forked-tongue raspberry. And while you’re there, feel free to add comments on my post and offer any tips you may have for dealing with vehicle-wildlife conflicts. You never know… maybe your advice will be featured further down the road.

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© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work; all you have to do is ask). Thanks to Tom Fischer Photography  for making his  work available through a Creative Commons license.

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foraging raccoon by Kara Allyson CC

One man's trash is another creature's feast (Photo: Kara Allyson, Creative Commons license)

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According to the U.S. Environmental Protection Agency (EPA), Americans throw out 34 million tons of food each year—an average of 93 thousand tons per day, and some experts estimate the amount triples on Thanksgiving and Christmas. Food for thought, while making another trip to the garbage can following our national day of feasting. Waste not, want not… so the proverb goes. But does anything digestible really ever go to waste? Only if you think food is wasted when humans don’t consume it.

red squirrel in trash can by Rémi Lanvin ccWe live on a planet where, if someone can eat it, bet your bottom dollar someone does eat it. Within a biotic community there are three basic trophic (feeding) levels:  producers, consumers, and decomposers. Producers transform energy from the Sun into sugar (i.e. food)—that’s the work of green plants. Primary consumers eat the plants, secondary or tertiary consumers eat the animals that eat the plants. Decomposers transform both dead plants and animals back into their abiotic components (e.g., water, nitrogen, CO2). All three groups work together to create food, move it through the community, and return the abiotics back to the environment for another trip through the system.

Food travels through the community in food chains and food webs. A food chain is a simplistic model, a subset, for illustrating the relationship between a community’s trophic levels. For example:

Sun > violets > caterpillars > black-capped vireo > sharp-shinned hawk > black vulture > bacteria

The food web is a more realistic and complex model of the relationship between members of the biotic community. It takes into consideration the fact that most consumers eat more than one thing—vireos don’t just eat caterpillars, they eat a variety of insects, insect larvae, and spiders; sharp-shinned hawks eat all kinds of songbirds, plus some small mammals, and an occasional large insect; black vultures will eat almost any kind of meat, although they seem to prefer it well “aged.” A species can, and usually does, belong to more than one chain within the web. Very little is wasted, and everything that lives eventually takes a turn at eating and being eaten (with the exception of modern humans in the “developed” world, primarily due to our funereal laws and customs).

herring gull at landfill by Jerry Oldenettel ccA large portion of the human population may have disentangled themselves from food webs, but we remain an indirect source of nutrition for many non-human animals, and not just those we feed intentionally, such as our companion animals and livestock. Easy access to consistently plentiful human-produced food waste is a primary reason behind the success of many wild species in urban and suburban habitats. Garbage is also one of the main sources of conflict between wildlife and humans. This is due, largely, to the fact that—and I’m sorry, but I don’t know how else to say this—the human race has some definite control issues when it comes to food.

The concept of owning food seems to be uniquely human, as is the idea that we should be able to stipulate who gets access to calories that we think of as “ours,” including future-food (crops and livestock), faux-food (from Petco or Wild Birds Unlimited), and former-food (garbage).

Skeptical? How many times have you heard a bird-feeding acquaintance complain when squirrels invite themselves to dinner? Or even when the wrong kind of bird drops in for a snack? How about the U.S. Department of Agriculture (USDA), which spends millions of dollars annually on research and other efforts to reduce or eliminate wild species that like to avail themselves to a helping of the harvest? Consider, also, the time, money, and energy spent trying to keep wild creatures out of garbage cans and dumpsters, so their contents can be transported to the landfill and buried to prevent other non-humans from turning it into a meal.

Of course, there are valid reasons for managing food waste, including aesthetics and hygiene. Garbage stinks, and no one wants to live in the middle of a kitchen midden. You may be willing to share your cast off cuisine with resourceful furred and feathered recyclers, but human neighbors tend to be less than forgiving about garbage-strewn lawns. Picking chicken bones and greasy bits of aluminum foil out of the Zoysia grass isn’t all that fun; even less so when you’re running late for work. It’s mornings like these when homeowners begin to formulate battle plans.

opossum in trash can by Gary Oppenheim ccIt’s a war we’ll never win. At its core, this is a first-come-first-serve, finders- keepers-losers-weepers kind of world, especially when it comes to food. Sure, a brief détente may be achieved through an exclusion technology arms race. Some may even seek vigilante justice against an individual opossum or raccoon, a flock of seagulls or crows.

Victory will be short-lived. There will always be more where those came from because our leftovers are the raw materials from which the next generation of wild dumpster divers are created. Urban wildlife are adaptive, creative, resourceful, and fecund. They are adept exploiters of the humans with whom they live.

Still, in most ways it’s a symbiotic relationship. They take the food we no longer want and, in exchange, add to our quality of life in ways that are easy to recognize and hard to measure. Moreover, by refusing to accept that we are masters of the universe they keep us humble. And for that, I am thankful.

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© 2011 Next-Door Nature—no reprints without written permission from the author. Thanks to the following photographers for making their work available for use through a Creative Commons license: Rémi Lanvin (red squirrel); Jerry Oldenettel (herring gull); and Gary Oppenheim (opossum).

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garter snake swallowing a whole fish

Who needs a knife and fork, or even molars, when you can easily swallow bites bigger than your head? (Photo: Jesse Palmer, Creative Commons license)

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Could there be a holiday more representative of the true nature of American culture than Thanksgiving? Considered the least commercial of our national holidays, yet the true theme of the day is consumption. Family, food, and football are all available in quantities large enough to cause a bit of indigestion. Moreover, the entire event is just a warm up, an appetizer that signals the start of a dietary and retail feeding frenzy.

A turkey is the holiday’s traditional mascot, not to mention the main course, but I’d like to suggest a different and even more appropriate talisman for a day devoted to stuffing one’s face—the garter snake (Thamnophis spp.).

color and pattern variation in garter snakesThought to resemble the fanciful bands that held up men’s and ladies’ hosiery in a pre-elastic era, garter snakes are as American as pumpkin pies and pigskins. The most widely distributed reptile genus in North America, you’ll find them slithering from sea to shining sea across 49 states, including Alaska—the only snake able to make that claim. Remarkable in their ability to adjust to a wide range of habitats, garter snakes live on purple mountain ranges, in amber waves of grain, across the fruited plains, and everywhere in-between.

The genus includes 26 species and dozens of subspecies. Most include the “garter” tag as part of their common name, but the western ribbon snake (Thamnophis proximus) and its subspecies are part of the tribe too. Morphologically diverse—even within a species—the unifying theme is one or more stripes that run the length of the body (with or without spots). Some, like the common garter snake (Thamnophis sirtalis), favor an understated tan or brown background with yellow stripes. Other color combos may include: red-orange, black, and creamy yellow (coast garter snake, Thamnophis elegans terrestris); black with a pale teal green stripe and red spots (red-spotted garter snake, Thamnophis sirtalis concinnus); and even a striking electric blue paired with black (Puget Sound garter snake, Thamnophis sirtalis pickeringii).

Garter snakes are not picky eaters, and this characteristic has also helped them to spread out across the continent. These legless wonders will eat just about member of the Animal Kingdom they can catch and devour, including slugs, earthworms, fish, frogs and toads, lizards and other snakes, birds (including their eggs and nestlings), and small mammals, including rodents.

You’ve heard the phrase “His eyes were bigger than his stomach”? Well, that’s never really a problem for an animal whose stomach, along with the skin, muscles, ribs, throat, and mouth, can expand to accommodate up to 20% of its body weight in a single swallow. Imagine the kind of advantage you’d have in an eating contest if you could loosen your jaw, open wide (150° compared to 45° for the average human), and send a whole turkey down the hatch! Chewing? Why bother? Snakes don’t. They don’t have the choppers for it, although some have a few small teeth that curve toward the back of the mouth and help the reptile “walk” the upper and lower jaws over and around their meal. Concerned about how to breath while a roasted 30 pound tom or hen is passing through your gullet? No worries… if you’re a snake your windpipe is located near the front of your mouth and can move out of the way. If you’re not a snake (and I mean that literally—your in-laws’ opinion doesn’t count)… you may want to reconsider using a knife and fork.

Still, when your favorite team is lining up for the opening kickoff on the 55” LCD HDTV with Surround Sound, and Grandma is standing between you and the game with a third helping plate and a look that says responding to her offering with “no thanks, I couldn’t eat another bite” may not kill her, but it will significantly shorten her life—you have to admit, the ability to swallow food whole would sure come in handy.

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© 2011 Next-Door Nature— no reprints without written permission from the author. Thanks to the following photographers for making their photos available for use through a Creative Commons license:  Frank Miles/USFWS (2 common garter snakes); randomtruth (coast garter snake); Jonathan Crowe (red-spotted garter snake); and Dan Dzurisin (Purget Sound garter snake).

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Young raccoon

Everyone needs a room of their own, and a little wild-proofing goes a long way to keep everything, and everyone, in their own place. (Photo: Alan Howell © Star Path Images, used with permission).

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Sinatra was wrong.

I’m sorry Ol’ Blue Eyes, but the line that says if you can make it in a big city you can make it anywhere doesn’t hold true for everyone. For a lot of wild species, especially those who can tolerate living close to human beings, Gotham—and nearly every other town and suburb—has some significant advantages over small-town and no-town life.

Such as…?

Let’s start with the basics. All living creatures need, at minimum, four things to survive: air, water, food, and space. Air is equally available in most habitats (generally speaking), so one place is about as good as another when you’re looking to put down roots. City mouse, country mouse—neither has an oxygen advantage. Call it a draw.

pigeon at a drinking fountainHowever, finding something to fill your stomach and quench your thirst can be a full-time job in undeveloped areas, while living near people pretty much guarantees that #2 and #3 on that list will be plentiful. Parched? Even in arid regions, even during a drought, water is much easier to find in the city. Think birdbaths, hoses, fountains, sprinkler systems, swimming pools, park ponds and lakes. Chalk one up for the city critter.

opossum foraging in a trash canHungry? You’ve got your birdseed, your suet, your stale white bread—people hand that stuff out like there’s no tomorrow. Then there’s the never-ending supply of second-hand snack dispensers, available in medium (trash cans), large (dumpsters), and big-gulp (landfills). Plus you’ve got your “repurposed” vittles—garden produce, fruit trees and bushes, grass seed, expensive landscaping plants, pet food… and pets. Advantage urbanites.

The one thing that’s hard to come by for both human and non-human city residents is quality real estate.  Actually, it’s the fact that food and water are so bountiful that creates the wild housing crisis. In “natural” habitats, these resources are finite so the creatures living there vigorously defend access to them by establishing territories to exclude new residents, especially during breeding season. In the built environment, as illustrated above, food and water are, for all practical purposes, limitless. The carrying capacity of an urban or suburban landscape is much higher than surrounding undeveloped habitat, in large part because food, in all its myriad forms, is removed from rural areas and trucked into the city on a daily basis.

European starling exiting a pipe gapMore food = more critters… but the space available for nesting and denning sites doesn’t expand at a similar pace. In fact, development removes many natural denning and nesting sites, so finding a nice traditional home takes more effort. Is it any wonder that urban wildlife—comprised primarily of the most adaptable of species—start thinking creatively about dryer vents, chimneys, attics, garages, decks, and sheds?

fox under shedThink of it from a wild perspective—with a little behavioral flexibility, they and their loved ones can be warm and dry, while someone else pays the heating bill!

Now, most of the people I meet fall into one of two major camps regarding wildlife: “love-love-love-it,” and “live-and-let-live.” It’s only after a human-wildlife conflict of some kind has occurred, usually resulting in an expense for the human, that people start bad-mouthing their furry, feathery, and scaly neighbors.

Prevention is the best conflict resolution strategy I know. Autumn is when many animals begin to look for a place to hide out from old man winter, and sunny fall days are also a great time to get outside and tackle those wild-proofing maintenance and repair chores around the house and garden. Once you’ve made it more difficult for squatters to move in, staying on friendly terms with next-door nature is a breeze. There’s a nice little bonus for doing your chores, too—by sealing up all those potential entryways you’ll keep out the cold winds, reducing your heating bill and your carbon footprint. Such a deal!

squirrel under the eavesHere’s your to-do list:

  • Remove overhanging tree limbs that serve as bridges to your attic and chimney
  • Ask a professional to cap your chimneys (and while s/he is up there, might as well have them do a little sweeping to reduce the chance of a flue fire)
  • Cover all attic vents with caps made of ½” mesh hardware cloth
  • Replace any loose shingles and rotting soffit and fascia boards (great time to check for evidence of termites, too)
  • Fill any hole ≥ ¼” in diameter with calk, hardware cloth, or galvanized sheet metal
  • Seal gaps around window air conditioners, cables, and pipes
  • Remove firewood and brush piles from next to buildings

For more helpful instructions, along with a wealth of information on humane methods for preventing and solving all sorts of human-wildlife conflicts, I highly recommend a book titled Wild Neighbors by John Hadidian of the Humane Society of the United States, available new and used from all the usual online booksellers.

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P.S.  Homes are but one venue where human-wildlife conflicts occur. To hear about a few others, check out last week’s With Good Reason broadcast/podcast, Beyond Campfires and Cookies. The focus of the second feature story is none other than yours truly.

© 2011 Next-Door Nature— no reprints without written permission from the author. Thanks to the following photographers for making their work available: Alan Howell/Star Path Images (raccoon, used with permission); SP8254 (pigeon, Creative Commons license); Jason Ahrns (opossum, Creative Commons license); John Haslam (European starling, Creative Commons license); David Ginsberg (fox, Creative Commons license); and Joel Down (squirrel, Creative Commons license).

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Deer crossing a road

Motorists are looking for ways to reduce collisions with wildlife, but do "deer whistles" or other acoustic devices really help? (Photo: iStock, used with permission)

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I’m finally able to share some news that has been in the works for several months. Car Talk, one of the most popular shows on National Public Radio, has named me to the newly created honorary position of AnimalVehicle Biologist. Together, we’ve developed a Wildlife and Your Car FAQ page for their website to address some of the more common questions they’ve received over the years, and I’ve agreed to help as new questions come in. So, in honor of Tom and Ray and all the lackeys at Car Talk Plaza, this week’s blog post is devoted to one particular auto-animal issue.


No matter where you live in the U.S. or whether mule deer (Odocoileus hemionus) or white-tailed deer (Odocoileus virginianus) are the more common species, the potential for a deer–vehicle collision (DVC) continues to increase.

An adult deer can weight between 150–400 pounds. You don’t have to do the math to know when a car hits something that large there’s going to be a lot of damage… to the deer, of course—they rarely survive a DVC—and often to the automobile as well. How much damage the car sustains depends on the size of the vehicle, speed, and a variety of other factors.

The driver and passengers are at risk as well. This may be as a result of the driver attempting to avoid impact, but human injuries also occur when the animal comes through the windshield: dead, or alive-and-kicking.

That’s not a pretty image, I know, but it has to be said.

So I can certainly understand the interest in using acoustic devices—sometimes known as deer whistles—to alert animals that a vehicle is near.  Believe me, I would love to tell you that deer whistles are a simple and inexpensive way to keep cars and deer far from one another. Sadly, that’s not possible.

There have been a number of studies on the subject including a 2008 publication by researchers at Utah State University (USU). Their work suggests devices designed to frighten deer, including deer whistles, are “ineffective.”

Why? The study offers two main reasons: 1) the stimuli can’t be perceived by deer—either the sound isn’t within the animal’s hearing range or it doesn’t travel far enough or it’s blocked in some way; or 2) the sound doesn’t trigger a flight response.

Think about it. Even if deer can hear the whistle, what in their experience would cause them to equate that sound with danger? Aside from the normal wariness caused by anything novel in the environment, why would a deer consider a whistle—or even a car, for that matter—to be cause for alarm? All of their other predators are careful to be quiet, so the kind of sound a deer would equate with danger is more likely to be a twig snapping or leaves rustling. Frankly, there doesn’t appear to be much in the deer’s evolutionary history that would prepare them to be cautious around cars, other than, perhaps, the fact that the vehicles are moving quickly.

This same USU study found that, aside from reducing the deer population, modifying roads and motorist behavior could help to reduce DVCs.  New technologies, including in-vehicle detection systems, look promising but more research is needed.

Meanwhile, what can you do to avoid a DVC?

  • BE ALERT—especially during early morning and early evening hours.
  • BE AWARE—there’s data behind the placement of those deer-crossing signs so live and learn (and vice-versa)
  • BE EDGY—keep an eye out for movement on either side of the road and just beyond the shoulder, especially when driving through agricultural or wooded areas
  • BE CALM—slowing down a bit will increase the time you have to respond if an animal does dart out in front of you… and it will lower your blood pressure, too.

You can also visit the Humane Society of the United States website for more information on driving with wildlife in mind.

Have a question about wildlife and other next-door nature? Send an email and the answer may turn up as a future blog post. And don’t forget to “Like” NDN on Facebook!

© 2011 Next-Door Nature— no reprints without written permission from the author.

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