Analyzing data on coyotes and fawns
(Reprinted from above link)
Let’s face it, you could easily forget Delaware was there.
It’s a tiny little state but Rhode Island is smaller so it doesn’t even have the distinction of being the smallest state. It once had a very favorable business environment for financial companies, making it an attractive home base for credit card companies but I’m not even sure that’s true anymore. My friend and former colleague Jamon Smith is the only person I know who has lived there.
But Delaware apparently has one thing going for it – almost no coyotes. Only nine have ever been recorded shot there and the state requires all coyotes taken there to be reported.
I learned this from a fascinating article on the Quality Deer Management Association website called “Born with One Hoof in the Grave.” Its about the role of predation in deer fawn mortality rates.
First let me say I’m no fan of coyotes. If they aren’t shot at early and often, they are too quick to lose their natural fear of man and become suburban and urban pests. While they are no big threat to humans, they are extremely hard on small pets and have been known to snatch dogs and cats right off front porches and even off an owner’s leash. I’ve seen them lurking around our neighborhood at the beach and I carry a pistol when I walk my dogs down there.
Anyone who appreciates the natural world does have to admire their ruthless efficiency as hunters and I’m sure they help keep rodent populations in check. But I’m surprised a fawn can survive in West Alabama the way the coyote population has boomed there.
However, the QDMA article’s point was that coyotes might not have the kind of impact on fawns that we might think. Researchers trapped more than 100 deer fawns in Sussex County, Delaware, and outfitted them with radio collars to study fawn mortality. No coyotes are known to inhabit Sussex County.
According to the article, fawn survival rates range from 35 percent to 65 percent throughout the country and predation, mostly by coyotes, is the major factor. But the deer tagged in Sussex County had a survival rate of only 45 percent. Deaths resulted from a variety of causes including malnutrition and disease.
Low body weight was the common strain among those that died. And fawns born to mature does consistently had higher body weights. The authors said the evidence raised the possibility that predators might only be eating the weak and diseased fawns that are going to die anyway.
And they cited situations where landowners have put extensive efforts into reducing predator populations without seeing a resulting higher fawn survival rate.
On the other hand, I once heard an Auburn University wildlife biology professor cite a study in which 10 fawns were collared and nine wound up coyote meals. There’s no doubt in my mind coyotes eat a lot of deer fawns and not all of them are fainting from hunger or wasting away from disease.
So, what does all of this tell us? First, I don’t think it’s any secret hunters usually give too much weight to the impact of predatory animals. Quail hunters frequently blame the decline in the quail population on hawks and coyotes eating mature birds when the real culprit is habitat loss. The exotic pasture grasses that now cover the state have done more to wipe out quail than feathered or fur-bearing predators. And the worst quail predators are snakes, raccoons, skunks and other nest predators that eat quail eggs.
So, I imagine the impact of coyotes on deer fawn survival is less than we might imagine.
That said, I would still encourage deer hunters and landowners managing for deer to shoot every coyote they see. While they might not reduce the population significantly, the pressure could still encourage coyotes to look for greener pastures. Coyotes go where they aren’t shot at.
Thus, trapping and shooting coyotes might not reduce the overall population but it could have a localized effect that could have a positive impact on someone’s land or lease.
On the other hand, burning down the woods and poisoning the lakes to get rid of coyotes might not be worth it. Consider the effort, expense and collateral damage anytime you consider a predator reduction program.
Finally, we might ought to reconsider the practice of shooting the biggest, fattest old nanny when we decide to take a doe for the freezer. The doe that has gone barren in her old age appears to be a myth. The study cited in the QDMA study indicates that mature deer nurture fawns more successfully than younger does.
It’s never a good idea to abandon common sense but everything is not always as it seems.