Using scents to fool the noses of predatory varmints

By Don “Doc” Sanders

Animals, especially at night, rely on their noses to lead them to a broad range of food sources. Hunters take advantage of this concept to attract deer and elk that are searching for their next dinner.

Famous University of Sydney ecologist Catherine Price, PhD, and her colleagues have published a study that details how animals use their sense of smell to find food. She also researched how animal owners may be able to use odors to lead astray fox, coyotes, and other predators, to prevent them from killing their livestock and pets.

This study really hits close to home for me. A raccoon got into the chicken coop my late wife Kristen maintained. Her chickens were all wiped out in one night.

The study also brings back memories of my parents, who every year planted a half-row each of marigolds and chrysanthemums in their large garden. These flowers weren’t for decoration. Instead, my parents used them as a superb natural defense to protect their vegetables from tomato worms, aphids and rabbits. 

Similarly, people burn citronella or spray garlic oil around their yards to deter mosquitoes. Why this works, though, is a mystery to me. But, apparently, mosquitos don’t like the odor.

The power of specific scents to deter or detract animals has been commonly overlooked. The role of animals’ sense of smell — or olfaction, as scientists call it — has been neglected, perhaps because humans haven’t hunted by smell to any degree since the days when Native Americans relied on their keen senses.  

Male dogs, as you’ve likely observed, are expert at using scent to defend and mark their territory. And did you know that a male dog can smell a female in heat up to two miles away? Dogs have a well-developed organ in their nose, the Organ of Jacobsen. I don’t know who Jacobsen was, but I can tell you that bulls and stud horses also have this sensory organ. This organ is why intact male dogs disappear from home for several days chasing a female in heat. And why bulls or stud horses will jump over a fence to demonstrate their affections for a female.  

Little research has been done, however, in how animals use their nose to identify food. Price, though, has spent more than a decade exploring this subject, as well as how humans can circumvent animals’ sense of smell to decrease the threat of predatory varmints. 

Methods for doing this, she’s found, include masking the smell of a food source (such as seeds, eggs or an animal you’re trying to protect), disguising its scent or spreading a similar scent all over the surrounding landscape to confuse a canid predator or grazing animal so that it ignores a certain smell when it’s on the hunt for food.

It’s also about hiding the food that we don’t want them to eat — an endangered bird or plant, for instance — by making it harder for them to find. Hopefully, these animals on the prowl will then seek easier food options and give up searching for what we’re trying to protect.

Price and her team ground-tested her theory, literally. They put a chicken flesh scent in Vaseline and spread it across a 1,000-hectare area (a little under 2,500 acres) where endangered shorebirds such as plovers nested. They did this about the area prior to the birds’ nesting season so that the scent was apparent before the nests were established. 

Because the goo was everywhere, the odor made it difficult for the ferrets and weasels to pinpoint the nests. Dr. Price’s research, in fact, reduced raids on the bird nests by more than 50%. This effect lasted a month.

Now here’s a problem that Ohio’s farmers like you may be familiar with: groundhogs. You may not be aware that they hate the smell of Irish Spring soap bars. All you have to do is keep the soap in the wrapper, punch holes through the paper, then place the bar of Irish Spring at the entrance to their den. This little trick allegedly keeps groundhogs away. 

It has been reported that these critters also don’t like plants with strong fragrances — mint, sage, basil, lemon balm, rosemary, thyme, chives and oregano. These aren’t high on my list of fragrances either.

Now I need to do some olfactory research of my own. That is, to find just the right scent for approaching — and not scaring off — a widow, to prime her for a dinner date. In my opinion Harry’s Post Shave Balm might work the best. But I’ll see what the research determines.

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