Best of the Pests
1 Apr, 2009 By: Dr. Bobby Corrigan Wildlife Management Professional
If you ask most wildlife biologists, naturalists, hunters, lay persons, or students from kindergarten to college to list out the first 10 wildlife animals that come to mind, it usually looks something like this: deer, wolves, hawks, coyotes, moose, raccoon, bear, owls, geese and eagles.
Paradoxically, not on this list are the most numerous — and most successful — of our wildlife fauna: Rodents.
I'm not referring to city rats and mice, which are the second and third most successful wild mammals after humans (and are, biologically and technically speaking, truly part of the wildlife fauna).
But why do these other wild animals make the list, while rodents do not? Mostly, it's because of visual appeal.
Scenes and animals with visual appeal usually mean press coverage on television and magazines (Nature, National Geographic). Also, wild animals large enough in size to be seen by the lay public, and during the day in our parks and open spaces, tend to impress us.
Yet, there's a big difference between human visual appeal and biological success. Watching a herd of deer foraging in a misty meadow, or an eagle soaring overhead, certainly presents greater appeal compared to watching a squirrel run up a tree or chipmunks down a hole. Indeed, much of the public refers to rodents as "darn varmints."
But deer, eagles, moose and the other "glamorous" wildlife species are relatively restricted in their distribution and numbers. Rodents, on the other hand, are spectacularly successful in this regard. They've colonized nearly every part of the earth and have adapted to a wide array of habitats.
Rodents are numerous, not just in their amount of offspring, but in the number species. The mammal order of Rodentia comprises the largest of all mammals, with approximately 1,687 species.
Relative to our discussion of inquilines and the business of wildlife management, the rodents of greatest abundance and business importance are the tree squirrels (gray, fox, pine and flying) and the ground squirrels (chipmunks, ground squirrels and ground hogs).
But what factors explain the success of these rodents? And how does understanding their biological success translate to our business success as wildlife management professionals (WMPs_?
The following are a few of the more important ones.
Chisel-teeth Tools
Rodents are referred to as the chisel-toothed mammals. The word rodent means gnawing mammal. Rodents possess two opposing pair of ever-growing, razor sharp, incisor teeth. These four teeth are more tools than they are teeth (the teeth of most mammals are designed for grinding food and starting the food ingestion and digestion process).
With tree squirrels and rats, the front incisor teeth are used as tools to create or access harborage by gnawing holes into trees, or the soffits, fascia board gaps, ridge boards of our buildings. Or, they gnaw small openings to enlarge them in order to gain access around the various pipe and cable utilities that penetrate buildings.
The incisors are also used to assist rodents in climbing rocky walls, or the exterior brick walls of your present and future customers.
The incisors are essential for rodents to have access to the foods of the wild, and to collect and transport such foods. They enable rodents to split open the shells of acorns and bird eggs, or to dispatch and eat insects small snakes, worms and grubs.
Incisors are also used to clip limbs and branches, strip bark, and gnaw down and disassemble various plant stems to access moisture, or to gather sticks, stems and leaves to construct warm nests. Inside your customers' attics, rodents may instinctively attempt to gnaw on an electrical wire — an item that visually appears similar in shape and size to twigs and branches. Ground squirrels use their incisors to cut through roots and tubers that may impede their tunneling and burrow construction.
High Reproductive Rates.
Most of the rodents in the urban wildlife group are classified as prey species. Thus, many mammals higher in the food chain are constantly killing and consuming rodents. To offset their losses to predators, rodents posses high reproductive potential. Most of the rodents important to WMPs produce multiples of young per litter and multiple litters in a year. In towns and cities, where many of the natural predators have been displaced, there are fewer checks and balances on the rodents. This, in part, explains why the services of WMPs have steadily increased in the past few decades.
Superb Gymnasts
If you're an experienced WMP, the physical dexterity and agility of rodents around buildings comes as no surprise to you. And, if you have seen any recent You-Tube videos on squirrels negotiating the Rube Goldberg bird feeder course, or National Geographic's Rat Genius movie, you were in awe of the physical and cognitive abilities of rodents.
It truly is amazing to watch rodents access difficult-to-reach food and harborages by jumping, leaping, climbing, swinging, contorting and tail leveraging. Urban rodents are, in fact, superb gymnasts. Most residential homes pose little actual resistance to a determined rodent.
Ground squirrels are not quite the gymnasts as their arboreal cousins, but they too are capable climbers and jumpers. In their subterranean world adaptations, they're highly agile and can negotiate impressive turns and twists within their tight burrow tunnels.
Putting It To Use
So rodents are successfully designed. But how does this help you, an on-the-job WMP, provide great service and maximize business profits by minimizing unexpected callbacks?
First and foremost, constantly remind yourself that rodents didn't become the most successful mammal pests on earth by accident. Think of them as being diabolically cleaver in their foraging abilities, anti-predator behaviors, and to the point of the question, their abilities to gain entry to attics, crawl spaces, wall voids, soffits and retaining walls.
Whenever you arrive at a client's property to provide wildlife management services for any urban rodents, the best route for efficient and profitable service is thoroughness.
Double check yourself in all inspections. Never be satisfied with the first hole, and certainly not the most visible hole you discover. As a result of their anti-predator behaviors, it's a good bet — and a clever one — there are additional holes hidden beneath, above or behind some structural element. Accuracy in your inspection allows you to be accurate in your service plan and maximize the profitably of the job.
In the most simplistic terms, the goal for us "wise" humans is to be more clever than the rodent. Certainly our customers expect this of us.
You can reach Corrigan, PMP Hall of Famer and president of RMC Pest Management Consulting, at mypmp@questex.com.
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