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Archive for the ‘mammals’ Category

Mexican free-tailed bat

Bracken Cave, in the Texas Hill Country, is home to the world’s largest colony of Mexican free-tailed bats. (Photo: © Merlin D. Tuttle, Bat Conservation International, http://www.batcon.org. Used with permission)

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When Doppler radar first arrived in the area known affectionately to Texans as The Hill Country, local television station meteorologists were understandably eager to show off the weather forecasting capabilities of their newest toy. Unfortunately, they got off to a less than impressive start. Night after night that summer, evening thunderstorms were forecast but failed to appear. This created distrust within the populace and confusion among the weather men and women. Eventually, someone figured out that Doppler couldn’t tell the difference between a microwave reflected by water droplets in the atmosphere and Mexican free-tailed bats (Tadarida brasiliensis) emerging from nearby Bracken Cave.

How many bats does it take to confuse Doppler radar? About 20 million.

Hundreds of Austin residents and visitors gather at the Congress Avenue Bridge every summer night to observe 1.5 million bats emerging to feed (Photo: © Merlin D. Tuttle, Bat Conservation International, http://www.batcon.org. Used with permission)

Several times in my life, I’ve had the privilege of watching, with barely contained glee, as Austin’s famous Congress Avenue bats poured out of the expansion slots below the bridge deck. With 1.5 million bats in residence, the city is home to the world’s largest urban bat colony. But the Bracken Cave colony dwarfs its city neighbor. It’s the world’s biggest, as well as the greatest known concentration of non-human mammals. Modern Americans will never have a chance to witness hordes of bison churning up the prairie or enormous flocks of passenger pigeons darkening the skies, but Bracken Cave—where it takes 4 hours for all the adult bats to stream out of the cave mouth and drift like smoke over Texas to feed—evokes some sense of what has been lost.

While in Austin a couple of years ago to attend the International Urban Wildlife Management Conference, I finally realized a long-time dream to witness this event with my own eyes. I was not disappointed. Bat Conservation International (BCI) owns the cave and the 697-acre buffer zone that keeps development at bay. The organization, which limits the number of visitors, graciously agreed to lead a group of conference attendees to the property, located near San Antonio.

During a brief orientation we learned that Bracken Cave bats migrate to Texas each spring from their winter home in Mexico, a distance of approximately 1,000 miles. The roof of the cave collapsed at some point in history, forming a perfect amphitheater from which to view the resulting entrance. Members of our group settled in twos and threes to watch, using small boulders as chairs and loveseats while we waited for the day to end and the main event to begin.

Bracken Cave is a maternal colony—no men allowed in this sorority—and soon after the females arrive, each gives birth to a single pup. Mexican free-tailed bat babies are not raised as only children; their mothers park them in a communal nursery set apart from where the adults hang out during the day. With as many as 500 babies per square foot of cave wall, the naked infants generate enough warmth to keep themselves cozy, freeing their mothers to leave each evening to cruise for calories. The downside of this arrangement? When it’s time to feed the offspring, Mom has to find her child somewhere in the mob—a task most human parents would find daunting.

The cave is not a home people would consider sweet. Millions of bats digesting millions of insects from March through October results in an annual deposition of 85 to 100 tons of bat feces, known as guano, on the cave floor. Experts estimate the guano may be 70 feet deep at the very back of the cave (and how one becomes an expert at estimating guano depth is beyond my ability, or desire, to imagine). As part of its stewardship of the site, BCI schedules periodic off-season “mining” of the guano—a practice that goes back to the late 1800s—which is currently sold as organic fertilizer.

As you approach the cave from a staging area near the property entrance, the distinctive, acrid smell of bat waste is hard to miss. Consider, if you dare, what it’s like underground. In winter, when the gals head south of the border to hook up with the guys and have the bat equivalent of a “Girls Gone Wild” experience, the cave is a comfortable 68°F; during the summer months, heat generated by all those bat bodies brings the ambient temperature inside to 108°F. Dermestid beetles are so abundant the floor writhes. The beetles feed primarily on guano, but any infant or injured bat who has the bad luck of falling is swarmed and consumed in minutes. Ammonia gas, a by-product of beetle digestion, fills the cave; levels inside are high enough to be fatal to humans so researchers must wear breathing apparatus to enter when the bats are there.

Personally, this is not the kind of place I’d choose to spend the summer. I lived in Texas for nearly 20 years and I have to say, the heat, humidity, and insect life above ground in July and August is as close to hell as I care to experience.*

Thankfully, during our field trip the air outside the cave was much more refreshing. It was a beautiful, clear, and blessedly temperate May evening, and before too long we began to see movement near the mouth of the cave. This show featured aerial acrobatics that would be the envy of any Blue Angel pilot. Bats were climbing, diving, banking, and stalling, making literally hundreds of mid-course corrections to avoiding collisions, while also attempting to evade the grasping hands of raccoons that gather near the mouth of the cave and the sharp talons of hawks circling above. It’s a dizzying scene, and the bats are both predator and prey.

What began as a small shower of bats quickly turned into a storm, with thousands of leathery wings mimicking the sound of a downpour. As their numbers continued to grow, they swirled and pulsed like a tornado, spinning in seemingly endless circles within the bowl of the sinkhole. Only after I raised my eyes from the dervish before me did I see a dark, smoky trail of bats stretching off beyond the horizon. And still the deluge continued all around us… bats, and more bats, and still more bats.

If, as Doppler radar would have us believe, bats are indistinguishable from raindrops, I’d have been drenched. And singin’, just singin’, in the rain.

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NOTE: Why are these bats called “free-tailed”? Because, unlike many species, the tail is not completely surrounded by a membrane, known at the patagium, that stretches between the animals’ legs—its at least partially “free” (see illustration below). The patagium also stretches between the fingers and connects the front and rear limbs to form the wing.

bat tails

Mexican free-tailed bat (left) and a Townsend’s big-eared bat (right)

*ok, I’ll confess to some hyperbole for the sake of the story. I actually enjoyed living in Texas, although less so during the summer.

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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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© 2011 Next-Door Nature— no reprints without written permission from the author. Thanks to Bat Conservation International for granting permission to use their photos. The drawings used above are open-source content.

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The Nissan Watering Hole (Photo: Ingrid Taylar, used with permission)

American robins and other wild creatures have to get creative if they want to quench a winter thirst (Photo: Ingrid Taylar, Creative Commons license)

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Which season comes to mind when you read these words?

parched

desiccated

shriveled

arid

sere

If you’re a wild thing, the answer may well be winter.

Sure, the heat of summer can make any body feel dry as dust. But wild animals, especially species that can tolerate living near people, usually have an easier time finding some moisture when the mercury rises than when it falls.

In cities and suburbs, April brings more than just spring showers. The return engagement of automatic lawn sprinklers turns every pampered landscaping leaf and each blade of carefully tended turf-grass into a diminutive drink dispenser. Fountains splash and spritz and spray. Swimming pools drop all pretense of modesty and shrug off their winter coats. Hoses report for car-washing and child-cooling duty, turning streets and sidewalks into ephemeral streams. Birdbaths and pet bowls brim with cool, clear water.

Squirrel lapping water from window (Photo: David Grant, CC license)Come January, February, and March, creatures have to get creative and a bit brave to quench their thirst, at least in northern climes. Those of us with easy access to indoor plumbing may not realize it, but for wild animals, dehydration is a bigger threat to winter survival than starvation. Even when the clouds are feeling generous, the precipitation they deliver is often in a more or less rigid—and much less quaffable—form. Personally, I like to think of sleet, snow, and ice as the H2O equivalent of hibernation. Unfortunately, water’s winter vacation means more work for those who depend on it.

And that’s everyone. No exception. Animal, vegetable (no, not mineral)… if you’re alive, you not only need to consume water, you are water—60 to 80% water. Even critters who sleep away the short photo-period months depend on water to stay alive, same as the rest of us. They simply tank up pre-torpor and then use the water tucked away in their extra reserves of body fat.

American goldfinch drinking from an icicle (Photo: JDB Photos, CC license)Active animals need water for basic metabolic functions, including proper digestion. This is especially true for seed-eating birds (a group that tends to hang around all year rather than migrate to places where insects and fruit are still on the menu) because there isn’t much moisture in their meals. In fact, it takes extra water to digest high fiber foods.

What happens to birds and mammals who can’t find a source of unfrozen surface water when they need it? The problem is far greater than simply putting up with a dry mouth until you can stop at a convenience store for a bottle of Aquafina. How long an animal can go without water depends on many factors, including their species, weight, physical condition, and parasite load, as well as the weather. Generally speaking, though, it doesn’t take long for life without liquid to get unpleasant. Lose one or two percent of total body water (TBW) and your dehydration is classified as “mild”; however, anyone who’s experienced it (that would be me) is sure to argue that the resulting headache is anything but. The definition of “moderate” dehydration is five to ten percent of TBW… the situation is getting serious now, as your skin dries out and loses turgor (the ability to snap back into place when pinched) and your eyes begin to sink back into their sockets. Over ten percent TBW loss is “severe” enough that you’re unlikely to recover without medical intervention.

The scenario I’ve just described may sound like an environmental disaster waiting to happen… and in cases of actual drought, such as what’s been going on in much of the U.S. the past several years, the impact is rather grim. Under more normal circumstances, winter water is difficult but not impossible to find, and this scarcity offers an opportunity for nature lovers. Want to make wild lives—and wildlife watching—a little easier? Turn on the spigot.

I mean that literally. Providing water can be as simple as letting your outside faucets drip. You probably already do this to protect your pipes from bursting when The Weather Channel warns of freezing temperatures. Perhaps you can afford to do it once a week, or every other day, regardless of the forecast.

BluebirdBath (Photo: Rob and Jane Kirkland, CC license)

If you’d rather keep the water bill low, and the wild ones a little further from the house, birdbaths are a simple way to offer refreshment. They’re easy to maintain, plus you can add an electric, battery-, or solar-powered heater/de-icer to insure that everyone can wet their whistle on even the coldest days. Hard-core backyard habitat aficionados will drool over the possibility of installing a pond or artificial stream. Whatever floats your boat—you’ll find both ends of the water-feature spectrum, and everything in between, at your local watchable wildlife retailer or gardening center.  I promise you, the sound of water is irresistible music to human and non-human ears alike. New resources will be found and greatly appreciated.

What’s more, water is an effective wildlife attractor all year long. When you offer seed, you get seed-eaters (e.g., cardinals, blue jays, house sparrows, and squirrels), some omnivores (e.g., opossums, raccoons, the occasional deer or black bear)—and probably a lot of hulls and other waste that needs to be raked up and thrown away. Feeder maintenance can be an expensive and time-consuming habit. [Be warned, you may also inadvertently lure in some species who like to feast on the feeder regulars. If you find it disturbing to look up from your morning coffee to see a sharp-shinned hawk scattering goldfinch feathers hither and yon, you may find it helps to think of this as progressing from “having a feeder” to “having a food-web.”] Landscape with native plants and you should be able to coax some fruit and nectar fans to visit as well. Few homeowners are willing to do what’s necessary to invite insectivores to dinner, at least intentionally.

But offer everyone something to drink and suddenly your crib is a coffee house, local pub, and hot new club, all rolled into one. Just add water!

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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!

© 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: Ingrid Taylar (thirsty robins); David Grant (thirsty squirrel); JDB Photos (thirsty goldfinch); and Rob & Jane Kirkland (thirsty bluebirds)..

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arctic fox by emma j bishop cc

There’s nothing quite as contagious as a yawn* (Photo: Emma J. Bishop, Creative Commons license)

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Grab forty winks. Saw logs. For a species that’s habitually short on shut-eye, we humans sure have come up with myriad ways to talk about it. We also spend a lot of time and money studying sleep, or the lack thereof. Yet, in spite of decades of inquiry, researchers still don’t have a good fix on why we—and just about every other living creature—need to nod off.  We’ve had better luck trying to understand other unconscious states, especially those employed by certain non-human species to deal with hard times.

yawning prairie dog by SearchNetMedia ccWinter poses a critical challenge for animals who stay put rather than migrate to warmer climes. Thermoregulation requires calories, but many foods—especially fruits, nectars, vegetation, and insects—are scarce when the days are short. The ability to reduce one’s energy needs can be a life-saving adaptation. Hibernation does just that—it lowers an animal’s metabolic rate. If all goes well, this period of inactivity, which may last several days, weeks, or even months, depending on the species, will stretch stored energy reserves (aka body fat) long enough for the animal to survive until a greener season. “If” depends on many factors, such as the abundance of autumn food resources, the length and severity of cold days, and even the stability of the den site during repeated freeze-thaw-freeze cycles.

When a critter—let’s use the chipmunk (Tamias spp.) as an example—transitions into a state of hibernation, its body temperature drops to near freezing, breathing becomes so shallow as to be imperceptible, and the heart rate decreases dramatically, from 350 to 4 beats per minute.  Although we tend to think of hibernation as a season-long slumber, chippies and other hibernating rodents do wake up every few weeks to have a snack and take a potty break, even though these periods of activity, called interbout arousals, consume up to 90% of stored body fat. There are some champion nappers in this chisel-toothed group—including the groundhog (aka woodchuck, Marmota monax), who sleeps half its life away, setting the alarm for March when it heads to bed in September.

Other examples of sound sleepers include: insectivores like the European hedgehog (Erinaceus europaeus) and the tenrecs (Microgale spp.); the mountain pygmy possum (Burramys parvus)—the only hibernating marsupial; and the echidna (Tachyglossus spp.), a monotreme.  Biologist recently added the mouse lemur (Microcebus spp.) and the fat-tailed dwarf lemur (Cheirogaleus medius) to the hibernator roster; prior to this discovery, we didn’t have any examples from among the primates. Additionally, since winter temperatures in their native Madagascar may reach 86° F (30° C), it’s become clear that hibernation isn’t strictly associated with cold weather. Nor is it limited to mammals; a bird called the common poorwill (Phalaenoptilus nuttallii) snoozes through at least some of the snowy season.

yawning polar bear by Paul Davidy ccIronically, that most famous of North American sleep icons, the bear (Ursus spp.), is the subject of many a drowsy debate over whether or not they are “true hibernators.” Bears often spend far more time sleeping than the so-called “trues,” so what’s all the fuss about?  Well, this is going to sound like nit-picking, but here goes. First of all, a bear’s heart rate drops, but not quickly enough to suit some scientists. Also, while the number of heartbeats may go as low as 8 per minute, the average is closer to 50 per minute. Moreover, during this time the bear’s body temperature remains pretty close to normal. This is a handy little idiosyncrasy that, should the need arise, allows the animal to wake up fast… and often cranky—a fact Santa (and anyone else) should keep in mind when planning a mid-winter visit to the den.

Taking to one’s bed for months on end could be seen as a rather over-the-top response to a simple cold front. It smacks of swooning characters in English romance novels from the late 1700s. Frankly, it’s not everyone’s cup of tea, and many wild critters take a more measured approach. Torpor is the term commonly used to describe these shorter, less dramatic forms of dormancy, although, technically, hibernation and other types of suspended animation are really subsets of torpidity. Call it what you will, there are examples of “temporary hibernation” in all the Classes of vertebrate animals—mammals, birds, reptiles, amphibians, and fish—and it’s commonplace among the myriad spineless critters as well.

For some of the busiest bodies, torpor is a daily habit. Hummingbirds (Trochilidae), for example, have such a high metabolic rate that they need to ingest a steady stream of non-carbonated sugar water (i.e., nectar) during their waking hours or they’ll become hypoglycemic and too exhausted to fly. Can’t fly? Can’t feed—a vicious circle that will ultimately lead to the bird’s death without some kind of intervention. As you might imagine, this need to constantly refuel creates an enormous problem when night falls and these feathered perpetual motion machines must rest. Without some way to temporarily lower their metabolic rate, hummingbirds would never be able to get out of bed in the morning. Never fear—torpidity to the rescue!

rock dove yawning by Tatiana Bulyonkova ccSwifts (Apodidae), chickadees (Paridae), nightjars (Caprimulgidae), and doves (Columbidae) are just a few of the other avian species who go torpid under various conditions. Generally speaking, these birds are fruit-, nectar-, or insect-eaters, and they tend to be on the small side (less than 80g). The snowy owl (Bubo scandiacus), at 1600-2950g is one exception to this rule, and biologists recently added a second, when it was confirmed that the tawny frogmouth (Podargus strigoides) goes torpid during Australian winters.

Personally, I find these new insights into animal behavior thrilling, because they reassure me that what we know about wild creatures is still a drop in the bucket compared to what we don’t know—there are worlds upon worlds waiting to be discovered on this blue gem of a planet we call home.

yawning turtle by Michael Ransburg ccOf course, cold is not the only hardship wild things would rather sleep through. Periods of drought are just as serious a threat to survival, especially for aquatic and semi-aquatic species. When a lake, pond, or stream goes dry, the inhabitants need to dig in. Literally. Turtles and tortoises (Testudines), crocodiles (Crocodylidae), frogs and toads (Anura), salamanders (Caudata), and some crustaceans will aestivate (also spelled estivate)—a drought-driven form of hibernation. They sink down into the mud before it dries completely, sealing themselves in a mucous capsule until the rains come again. If ever there was a time to be glad you can absorb oxygen in the soil through your skin, this is it, because the air in your boggy bubble won’t last very long.

yawning snowy owl by Pat Gaines ccResearchers are intrigued by these alternate forms of sleep and how they might offer clues for solving a variety of human health concerns. Honestly, I understand their fascination but I don’t know how they stay awake long enough to collect any data. Just writing about dormancy has my eyelid feeling so… heavy. I guess it’s… time for…. me to turn… in.

…..Hit the  [YAWN!]  hay.

……….Catch some…..zzzzzzzzz

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*Pop Quiz:  How many times did you yawn while reading this? 😉

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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!

© 2011 Next-Door Nature—no reprints without written permission from the author. Thanks to these photographers for making their work available through a Creative Commons license: SearchNetMedia (prairie dog); Pau Davidy (polar bear); Tatiana Bulyonkova (rock dove); Michael Ransburg (turtle); and Pat Gaines (snowy owl).

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next-door nature, urban wildlife, fence lizard

Everyone, even fence lizards and other ectothermic creatures, are feeling the heat these days (Photo: Bandelier National Monument, Creative Commons license)

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Temperatures across the southern half of the U.S. are soaring into triple digits, so I was trying to think of creative solutions to beat the heat when it hit me—why not become cold-blooded!

next-door nature, urban wildlife, fox squirrelAlas, my brain must have overheated. Once air conditioning allowed a cooler head to prevail I realized that what seemed like a brilliant idea while baking beneath a blazing sun is absolutely, completely, utterly impossible… and not simply because mammals cannot will themselves to undergo metamorphosis.

You see, technically there’s no such thing as a cold-blooded animal (unless you’re speaking metaphorically about someone who lacks emotion or empathy).  Or a warm-blooded animal, for that matter. Both terms are shorthand for the ways in which body temperature (aka thermophysiology) is controlled in different types of organisms.

Most mammals and birds are classified as endotherms (Greek: endon = within; thermē = heat). For these critters thermoregulation is an inside job, primarily by way of metabolic processes. Under extreme environmental next-door nature, urban wildlife, sunbathersconditions some physical mechanisms come into play, but not solar energy (at least, not directly). If the mercury plummets and the body’s core temperature begins to drop, muscles shiver to create warmth; if the core temperature starts to rise the body perspires to cool via evaporation. No sweat glands? Pant like a dog… or birds. All evidence to the contrary, since humans are mammals, swimsuit-clad sunbathers dozing in rows on a beach or poolside with icy drinks standing at the ready are, in fact, capable of maintaining a relatively constant body temperature.

next-door nature, urban wildlife, gray treefrogWhen an animal’s body temperature is strongly influenced by ambient conditions it’s an ectotherm (Greek: ektós = outside). Fish, amphibians, reptiles, and invertebrates rely on external heat sources to get their juices flowing, especially during the chillier seasons or cooler times of day. That’s why these animals can be seen basking on rocks, roads, and any other warmth-radiating surface. Then, when they can’t stand the heat they get out of the kitchen, retreating into shade, water, or underground to cool off (Sound familiar? We really are more alike than different).

Take-home message: mammals and birds are endotherms; invertebrates, fish, amphibians, and reptiles are ectotherms.

Except when they aren’t.

It’s the exceptions that make the rule, right? Let’s begin with the usual ectotherm suspects. According to one source, 2% of invertebrates are endothermic. Regrettably, the informant failed to name names but, in spite of the fact that spineless animals are not my strong suit, I did managed to chased one down—snails and slugs (Oops, that’s two… and “chased” may be overstating things).  Fish, being vertebrate species, are my regular beat so I can state with certainty that billfish (e.g., sailfish, marlins), tuna (Scombridae), one family of sharks (Lamnidae, including makos and whites), and one species of mackerel (Gasterochisma melampus) are endothermic… at least to some degree. I’ve yet to find a reliable report of an endothermic amphibian, but among the reptiles sea turtles exhibit both ecto- and endothermic traits.

next-door nature, urban wildlife, echidnaMoving along to the endothermic exceptions… Hummingbirds (Trochilidae), swifts (Apodidae), and common poorwills (Phalaenoptilus nuttallii) all experience periods of lower body temperature and metabolic rate; therefore, some biologists argue they have ectothermic traits. Additionally, there are mammals—certain rodents, a couple of lemurs, and many bats—that enter hibernation or estivation in response to low temperatures or drought, respectively. Then there’s the echnidna (Tachyglossidae), a “primitive” mammal from Australia that’s an ectotherm eleven months of the year and an endotherm during the month when it lays its eggs (Yes, eggs. If you like rule-breakers Australia is your Mecca. In the interest of time and space, though, we’ll have to save monotremes for another day).

What I’ve presented above is a fairly simplistic description of thermophysiology.  Why stop there? Because a more thorough treatment would require a good deal of nuance and a complicated discussion of sub-categories, not to mention a stiff drink (the current temperature is 99°F and rising—make mine a frozen margarita).  But since it’s so hot I’ll go ahead and venture past a toe in the water… up to my knees, but no further.

next-door nature, urban wildlife, elephant shrewOne subset of the endotherms are tachymetabolic (Greek: tachy = quick), organisms with a consistent and extremely high metabolic rate. Shrews (Soricidae) are a perfect example—diminutive beings with massive appetites, their metabolic rate is at least five times that of similarly sized ectotherms. Being able to snack non-stop and still rock a bikini probably sounds too good to be true. It is. Finding a constant supply of calories without access to fast food and grocery stores is no picnic. Bradymetabolic (Greek: brady = slow), which could easily be mistaken for bipolar disorder, is no bed of roses either. These organisms swing wildly between a high (when active) and low (when resting) metabolism, usually based on either external temperatures or food availability. (If you think someone else has got it better, rest assured you probably don’t know the whole story.)

As biologists refine our understanding of how bodies work, language evolves and once popular terms like cold-blooded fall from favor. Popular stereotypes suggest otherwise, but scientists are not completely immune to trends. When I was an undergrad, for example, the preferred word for organisms influenced by changes in ambient temperature was poikilotherm (Greek: poikilo = varied, irregular). Although still useful for making distinctions between types of ecotherms, the term is used less frequently now and may be on it the way out.

next-door nature, urban wildlife, crocodilesC’est la vie. Styles change, in both the lab and on the beach (Thankfully. I’m old enough to remember when Speedos were all the rage in men’s swimwear). I’d be willing to bet, though, that most Earthlings won’t give up sun worship any time soon. Chillin’ in a sunbeam feels too good, whether you need it or not (at least as long as there’s a pool nearby).

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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 first.). Thanks to these photographers for making their work available through a Creative Commons license: Bandelier National Monument (sunning fence lizard); Michael V. Flores (fox squirrel cooling down); Nick Papakyriazis (sunbathers); geopungo (gray treefrog); BohemianDolls (elephant shrew); and Jess Loughborough (basking crocodiles).

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next-door nature, mountain lion, cougar, dispersal, Midwest

Cougars are one of several predator species returning to historic ranges, even when they include highly developed areas (Photo: Wayne Dumbleton, Creative Commons license)

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Midwesterners are welcoming the return of some long-absent natives.

On second thought, “welcoming” is probably an overstatement… because just as in the famous biblical parable, not everyone is thrilled about this reunion.

A rigorous statistical study to be published in an upcoming issue of the Journal of Wildlife Management confirms the presence of 178 cougars (Puma concolor) in the Midwestern U.S. states of Missouri (10), Nebraska (67), North Dakota (31), Oklahoma (12), South Dakota (11), and Texas (12). Single incident reports were documented in Arkansas, Illinois, Iowa, Kansas, Louisiana, Michigan, Minnesota, and Wisconsin.

next-door nature, cougar, mountain lion, historic photo, market huntingOnce found throughout North America, from the Canadian Yukon south to the Chilean Patagonia and all 48 contiguous United States, cougar populations dropped precipitously over most of their historic range following European colonization of the continent. The 19th and early 20th centuries, in particular, were hard times for all wild predators. Eradication programs aimed at protecting livestock interests were common. Bounties for cougar pelts, combined with sport hunting and a reduced prey base, lead to extirpation of the species east of the Rockies, with the exception of a small subspecies population in Florida (the Florida panther, Puma concolor corryi).

You’ve heard of a coat of many colors? How about a cat of many names? Cougars are almost interchangeably known as mountain lions and pumas, but regional variants include catamount, panther, painter, ghost cat, screamer… and that’s just the English nomenclature.

The cougar has had more than it’s share of scientific names, too. Originally considered the largest member of the Felis clan, a genus that includes both the domestic cat (F. catus) and the somewhat larger jungle cat (F. chaus), in 1993 taxonomists created a new Puma group based on similar genetic structure and composed of two members—P. concolor and P. yagouaroundi, the much smaller jaguarondi, found in Central and South America. Another homecoming of sorts, I guess you could say, although whether the members are happy about their new blended family is anyone’s guess.

As the forth largest of all the world’s cats, adult cougars reach shoulder heights of between 24-35 inches (60-90 cm), nose-to-tail lengths of between 6.5-8 ft (2-2.4 m, females and males, respectively), and average weights of 100-150 lbs (42-62 kg; females and males, respectively).  It’s interesting to note that the closer a cougar lives to the equator the smaller it will likely be; the largest cougars are those found closest to the poles.

The species gets its name from the Latin word for “plain” or “one color” and that’s generally true for individual animals (as long as you ignore the lighter belly, throat and chin). At the population level there’s significant color variation, from golden to silvery-grey or even coppery-red. Cougar kittens don’t start out concolor—they are spotted with ringed tails but these markings fade as the youngsters mature.

next-door nature, cougar, mountain lion, dispersal, historic range, midwestAdult cougars have a sleek but muscular physique and are able climbers and strong swimmers, with exceptional leaping and powerful sprinting skills. Despite their speed, these cats are typically ambush predators that quietly stalk and then, if possible, drop silently down onto prey from above, breaking the neck or delivering a suffocating bite.

Cougars are obligate carnivores, which means to survive most of their calories must come from meat. What’s less important is whether the main course is mouse, squirrel, rabbit or raccoon, mutton, venison or veal. This failure to discriminate between wild game and domestic livestock has resulted in a long and bitter feud with ranchers that continues to this day.

The 1960s, however, were witness to a sea change in American attitudes toward the environment in general and predators specifically—at least in the urban and suburban areas that were rapidly becoming home to a majority of citizens. Public pressure to change management policies created greater legal protection for cougars and their numbers began to increase. Over subsequent decades, pressure to disperse has obviously increased as well, as western cougar habitat reaches carrying capacity.

Which brings us right back to where we started, with cougars recolonizing the center of the continent. They use what researchers call a “stepping stone” pattern. Young animals say goodbye to Mom (male cougars are absentee dads) and go looking for adventure. Travel the highways and byways, stop at an interesting locale, scout out dating and dining options then move along. Sometimes quite far along… as was the case with a male cougar who made it to Connecticut before being hit and killed by a vehicle.  Leaving home is what most young mammals, including humans, are programmed to do. I’m as good an example as any, having dispersed from Missouri at 21 to explore all three North American coasts and beyond.

next-door nature, cougar, mountain lion, dispersal, midwestCougars may have returned to their old stomping grounds but don’t expect fireworks or any other hoopla. As a native who left the area and has returned many times (although never to stay) I can assure you this homecoming will be a low-key affair.

We Midwesterners don’t like to call attention to ourselves, you know.

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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 first.). Thanks to these photographers for making their work available through a Creative Commons license:  Wayne Dumbleton (cover); USFWS/Public Domain (historic photo of a market cougar hunter); Anthonut (profile); Susan Shepard (climbing down); NaturesFan1226 (sharpening claws).

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wildlife and roads, wildlife watching, wildlife habitat

Roads are both a blessing and a curse for wildlife (Photo: Colleen Greene, Creative Commons license)

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Ever dreamed of going on a safari? Then fasten your seat belt, start the engine, and hit the road. Any road. I’ll bet you dollars to donuts—take the time to look and you’ll spy enough wildlife to satisfy, Bwana.

Sure, some of the creatures will be easier to spot than others… for the simple reason they’re no longer moving.  But I’m not proposing a road-kill road-trip. Trust me, the city streets, shady neighborhood boulevards, highways and byways offer plenty of opportunities for wildlife watching. Naturally, the species on display depend on the size of the road, its location, the season, time of day, and the speed limit.

wildlife and roads, vultures, wildlife watchingLet’s say your motoring down a divided highway, a conduit to and through the all-American suburbs. The big stuff (aka megafauna), such as deer, elk, moose, bears, and even coyotes, can be seen at 65+ mph (although not always in time to either admire or avoid them). Certain birds of prey, red-tailed hawks in particular, can be seen at both speed and distance due to their habit of hanging out high on handy utility poles to scout for snacks. Anything more petite will be visible only if it’s on the shoulder or trying to cross the road. Scavengers looking for a free lunch can be seen out on the open road day (crows, ravens, vultures) and night (opossums, coyotes). That meal ticket can quickly turn the diner into dinner for someone else… and so on.

wildlife and roads, wildlife watching, groundhogBeyond mowed blacktop borders, in the woods and taller grasses, you’ll find rabbits, foxes, raccoons, skunks, and groundhogs. Based on my own non-scientific observation, to improve your chances of seeing these meso– (medium-sized) species as well as small but brightly colored male songbirds in situ you’ll have to ease up on the gas pedal and let the speedometer drop to 35-45 mph, tops.

A bicycle (or even a horse if you have access to one) would probably set the right pace for a rider to notice mice and voles, lizards, turtles, frogs and toads, as well as female songbirds (who tend to have less flashy wardrobes than their ready-for-the-disco menfolk). The truly diminutive critters—insects, spiders, snails and slugs—are hard to spot at more than arm’s length so it’s best to set off on foot and plan for a leisurely pace if spineless quarry is your goal.  A general rule: the slower you go, the more you’ll see—that’s what makes the backroads more appealing for this kind of trip than a superhighway.

In poetry, novels, song, and cinema people often speak of the allure and romance of roads—the ones that calls us, the ones less traveled, the ones that go on forever, choosing between high ones and low ones. Wild animals rarely have access to books and mp3 players and RedBox kiosks, though, and I’ve never found them to be all that interested in popular culture… so what’s the attraction?

To build a road through a previously undeveloped area, the first thing that happens is clearing a swath of the existing plant community, be that trees and shrubs or grasses or cacti. Once the project is completed (or even while it’s still in progress) new plants begin to colonize the bare soil, creating a plant community that’s different from the surrounding landscape along with an edge where new and old meet.  Disturbing the soil stimulates the germination of seeds that may have sat dormant for a long time waiting for the right conditions. Soil may be brought in from somewhere else as part of the construction process along with seeds from plants that are completely novel in this setting.

wildlife and roads, wildlife watching, wildlife habitatSince the plants predict what kind of animals will be found in any ecosystem, the new habitat creates opportunities certain wildlife species will exploit… but in most cases it won’t be the species that were living happily in the pre-construction habitat. Edge species will colonize the area, often using the right-of-way as a travel corridor before and after the road is completed. Some organisms will hitchhike to their new home on and in the bodies of larger animals or even motor vehicles. Birds, bats, and flying insects will drop in from above. Wild things are always jockeying for space and there’s no such thing as a vacant lot in nature—at least, not for long.

wildlife and roads, wildlife watching, pronghornMake no mistake—roads are a significant cause of habitat loss and their presence is detrimental to many types of wildlife. For others, though, the resulting edge provides exactly what they need to thrive. This includes our most familiar next-door nature species. In fact, the reason blue jays, robins, white-tailed deer and other edge-loving species are so common in human communities is because Homo sapiens is also an edge-loving species. Our roads are simply one very conspicuous example of that fact.

The natural world is never static; it’s always in flux and each day there are new winners and losers.  Are roads good or bad for wildlife? It depends on the species. But there’s no doubt they are a boon for wildlife watchers.

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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 first.). Thanks to these photographers for making their work available through a Creative Commons license: Colleen Greene (black bear); e_monk (black vulture); Matt Reinbold (groundhog); MoDOT Photos (edge habitat); Allan Harris (pronghorn).

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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.

Start your day with a little Next-Door Nature—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!
© 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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