Wednesday, September 16, 2020

Roadkill Blues

On the way to Tractor Supply, I passed what looked like a dead coyote. I turned around to make sure.

Yep; a young dead coyote — the second one of the day. This animal was in no condition to closely inspect, but it was probably a juvenile male doing “walk about” to find its own territory. A lot of the fox and coyote struck by cars this time of year are young males.

Roadkill is a 20th Century phenomenon, which is to say that we did not have it in the 19th Century when the roads were populated by horses and carriages.

Oh sure, we had some train kills -- deer and moose and cows and buffalo, but that's TRACKkill, not roadkill. And, of course, some horses died on the road from exhaustion or being shot, but they too were not roadkill as we define it here -- animals dying from vehicle impact on the road.

In fact, roadkill is probably the wrong term, even if it is the one we use. *Carkill* is what this really is; the road, after all, is simply a passive observer.

The problem with the term "carkill," is that it puts us in the picture. Roadkill, however, is a term that conveniently assigns millions of drive-by deaths to an inanimate object. It is a comforting term that absolves us of guilt.

Today, the Mercury Cougar (Automobilus detroitus) does some of the pruning work once done by the wolf (Canus lupus). Which is not to say Ford, Chevy, Toyota, Volvo, Mack Truck, and all the rest are not doing their part as well. They are.

Roadkill is not a small biological phenomenon, it is a BIG one.

In the small state of Virginia, there are over 35,000 deer-car impacts a year. In Michigan, deer impacts are so pervasive (over 55,000 a year), that they use deer roadkill data to determine the deer population in the woods. In Pennsylvania, another 40,000 deer a year fall under the wheel.

What's the national tally? Who knows? The number 350,000 is tossed around, but that seems too low. That said, not all states have as many deer as Virginia, Pennsylvania and Michigan, or as many drivers on dark or twising roads. So who knows? Whatever the number, it's clear that it is a lot.

Though I have no doubt that Darwinian forces are slowly playing out between animals and cars, the time-frame is still far too short. As a result, as brilliant as a squirrel is at figuring how to get to, and jimmy open, a bird feeder, it is still completely flummoxed by squealing tires and 4-cylinders. As a result, squirrels die in droves from vehicle impacts -- perhaps 40 million a year according to one back-of-the-napkin bean counter.

A few more sobering roadkill numbers, and some descriptive reasons as to why some animals are more likely to die on our highways than others:
▪️Dogs: It’s been written that 1.2 million dogs are killed on U.S. roads every year, but that seems dramatically high. That said, the number is not zero! Most dogs are killed in the daylight while chasing a ball, child, cat, or squirrel. Fences and leashes keep dogs alive. No fence and no leash, and the result is predictable.
▪️Cats: Cars kill about 5.4 million cats per year -- more cats than are killed in all U.S. animal shelters. Most cats are hit by cars at night.
▪️Snakes: Snakes are cold-blooded and will warm themselves on asphalt, especially on poorly-traveled rural roads in early Spring. Because snakes are small and easily obliterated by tires, there is no good data, but the numbers are clearly huge.
▪️Opossums: Opossums feast on roadkill, a habit that results in about 19 million opossums a year getting squashed. Possums are naturally slow, come out at night, and will often freeze in the headlights of a car.
▪️Skunks: When threatened, a skunk's natural defense is to turn its back and spray -- a technique that does not work too well with cars. Most skunks are hit at night.
▪️Turtles: Turtles and tortoises are killed in huge numbers, usually in late Spring and early Summer when they are moving around to mate and find suitable ground in which to lay eggs.
▪️Groundhogs: An estimated 5 million groundhogs or woodchucks get hit by cars every year. Groundhogs are diurnal, but because so many den along roadside embankments in order to take advantage of soft dirt, good drainage, fewer predators, and good forage, they are often living just yards from traffic. Sure this is maladaptive, but groundhogs have not been programmed with cars in mind.
▪️Raccoons: Raccoons frequently scavenge in roadside water ditches, are not too fast, are fairly belligerent, sometimes travel in trailing family groups, and hunt at night. Which is a nice way to say there are a lot of vehicle-raccoon impacts -- perhaps 10 million a year, maybe more.
▪️Fox and Coyote: Red fox are field-and-edge creatures, and are much more likely to be hit be a vehicle than a Gray fox which will generally be found in deeper woods and rocky areas. That said, both Red and Gray fox are night time scavengers, and as such are prone to being struck on the road while feeding on the carcass of a snake, possum, rabbit or squirrel previously struck by traffic. The saving grace of Red Fox and Coyote are that they are very fast and extremely wary -- the two chief reasons you see fewer dead fox and coyote than you do dead raccoons and possums.

2 comments:

Edze said...

I read an interesting article about a swallow type bird a while ago (sadly don't remember the species, I'll try to find out). It lives in a very urbanized area. Their wings are long and pointy, good for long distance flight, not so good for quick manoeuvring, especially direct after take off.
Researchers found out that their wings in this particular area, on average are slowly becoming shorter and more rounded. Exactly what you need when you have to make a life saving sharp turn when you are taking to the air to avoid getting run over by a car.
Evolution. It 's happening before our eyes.

Edze said...

Addition to earlier post; easier to find than I thought,here is the article: https://www.nature.com/news/swallows-may-be-evolving-to-dodge-traffic-1.12614