September 18, 2019

Meta-Analysis, Coyotes, and Lyme Disease

Recently I had posted a link to a “study” conducted at Pepperdine University about the diet of Northeastern coyotes, compared to Western coyotes’ and a possible link to the spread and/or perpetuation of Lyme Disease in the Northeast.

On March 4, 2018, I wrote an article sharing, in part, the publisher of Maine Sportsman Magazine, Jon Lund’s, observation that the increased population of coyotes in Maine was causing an increase in Lyme Disease-carrying ticks which in turn was the cause of up-turns in the incidences of the disease. I wrote: “In the March 2018 edition, he asks, “Are Coyotes to Blame for Increase in Ticks?” His simple explanation is that the presence of an increased population of coyotes in Maine is causing a reduction in the fox population – the trickle-down effect of an increase in ticks, particularly the tick that carries Lyme disease. The reality is that coyotes compete with and kill, directly and indirectly, the red fox that is sufficiently more adept at killing the small rodents that carry and perpetuate the Deer (Lyme) tick. In an effort to mitigate what appears to be a festering and growing incidence of Lyme disease in Maine, Lund is wondering if it is time, due to the necessity of a public health risk, to make a more serious effort at reducing the coyote population.”

According to the Meta-Analysis linked to, their conclusions do not support Lund’s theory. While I only have the Abstract of the study, I can only provide what is written there. But first, let me explain something in case readers don’t know what a meta-analysis is. A meta-analysis is “a statistical analysis that combines the results of multiple scientific studies.” (Source)

In this instance, scientists simple took data from 18 different studies about coyote diet and determined that while coyotes in the Northeast readily ate more deer, they proportionately did not eat more or less small predators (like the fox that Lund claims eat the rodents that carry the Lyme tick). The Abstract states: “Our results show that deer occur significantly more in the diet of Northeastern coyotes than in the diet of Midwestern coyotes, while small mammals occur significantly less. The occurrence of rabbits, hares, birds, vegetation, and fruit do not differ significantly by region. This supports the hypothesis that Northeastern coyotes, due to their larger size and hybridization with wolves, are better adapted at hunting large prey. Although Northeastern coyotes eat fewer small mammals than Midwestern coyotes, small mammals are still a common component of the Northeastern coyote diet. Thus the abundance of Northeastern coyotes is not likely to be positively correlated to the incidence of Lyme disease.”

It’s worth pointing out a few things. Again I’ll state that I don’t have access to the full study, however, there does seem to be some degree of contradiction but that contradiction may be insignificant.

Second, it appears from this information that because the Northeastern coyote eats far more deer, due mostly in size and cross-breeding with wolves, it may be due to a bigger appetite because the animal was bigger than the Western coyote. A conclusion on my part.

Third, this information clearly states that Northeastern coyotes eat fewer small mammals than their Western counterparts, but evidently not enough to make any sort of difference.

Fourth, this study concludes that it is “not likely” fewer small mammals consumed “positively correlated to the incidence of Lyme disease.”

It would appear that this analysis has only proven that Northeastern coyotes eat more deer than Western coyotes.

There is nothing conclusive, that I can see, that the presence of an increased population of coyotes has no effect on Lyme ticks.

Do any of the studies have data that go back to a time before the “Eastern coyote” became an invasive species? Have any of these studies taken place in long enough periods of time to take into account a changing coyote diet due to changing conditions on the ground? In other words, depending on conditions on the ground, a coyotes’ diet can have large fluctuations in amount and prey diet. Are these factored in? Will a changing diet also change the incidence of Lyme disease?

There are a lot of questions that remain unanswered. Because of this meta-analysis, I wouldn’t be too quick to disregard Jon Lund’s hypothesis about the direct correlation between coyotes and Lyme disease.

What got along superbly before the invasive species arrived. I would surmise we could get along marvelously without them now.

 

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But Where’s the Photo Showing What Dragged Off the “Coyote” Bait?

Two days ago the Bangor Daily News ran a story of how a man took a “roadkill” deer and hung it up for “coyote” bait. He set up a game camera and captured pictures of a bobcat feasting on the dead deer.

In retelling his story to the Bangor paper, the man said, “Two days later, we returned to find out the entire carcass had been dragged off by what appeared to be either a big single critter or a pack of critters, judging by the drag marks.”

Putting this all in context, this story references a previous story published in the Bangor Daily News about whether or not mountain lions are found in Maine. The man who hung the “coyote” bait and captured the photos says he believes what one wildlife biologist said about mountain lions in Maine and produced the story and pictures as a claim to support that big cats can be found in Maine…maybe.

My question is this. If this man got pictures of a bobcat chewing on a dead, hanging deer with his game camera, and he claims that “a single big critter or pack of critters” carried away the entire hanging dead deer, where are the pictures?

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Disease-Carrying Mutt

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Can coyote predation risk induce reproduction suppression in white-tailed deer?

Abstract

Predators can have powerful nonconsumptive effects on their prey by inducing behavioral, physiological, and morphological responses. These nonconsumptive effects may influence prey demography if they decrease birthrates or increase susceptibility to other sources of mortality. The Reproductive Suppression Model suggests that iteroparous species may maximize their lifetime reproductive success by suppressing their reproduction until a future time, when conditions may be more favorable. Coyote (Canis latrans) range expansion in the United States has exposed white-tailed deer (Odocoileus virginianus) populations to increased predation risk, and coyote predation can have profound effects on white-tailed deer reproductive success. We evaluated effects of temporal variation in predation risk (i.e., coyote–deer ratios) on fecundity and reproductive success of white-tailed deer on the Joseph W. Jones Ecological Research Center in southwestern Georgia, United States, by exploiting a rapid decline in coyote abundance to establish a natural experiment. We measured fecundity by examining ovaries for evidence of ovulation, and measured reproductive success using evidence of lactation from deer harvested before and after the decline in coyote abundance. We found that incidence of ovulation and lactation increased following the decline in predation risk. Our results suggest coyotes may be able to influence deer recruitment, independent of direct predation, through interactions that result in reduced fecundity. More broadly, our study suggests that in order to understand the totality of the effect of predators on prey population dynamics, studies should incorporate measures of direct and indirect predator effects.<<<Read More>>>

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Wolf Species Are Part Coyote

Gray wolves, pushed to near extinction in the 1960s, have roamed North America alongside two other wolf species—the red wolf in the southeastern U.S. and the Eastern wolf in the area surrounding the Great Lakes. But an analysis of their genomes has revealed a surprise: they are all actually one type of wolf, with varying amounts of coyote DNA, a study reported this week (July 27) in Science Advances.<<<Read More>>>

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Deer and Fawn Take on Attack From Coyote

I’m guessing this is a coyote judging from the longer, pointed ears and curled up tail.

CoyoteDeerSpar

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Merry Coyotemas!

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Coyote Attacks Boy in Chicago City Park

“Farmers and hunters have long lamented the problems coyotes present when it comes to livestock and deer populations. As it turns out, even city folks are having ‘yote problems.

According to WLS-TV in Chicago, a 3-year-old boy was bitten on the face by a coyote while walking with his mother near Columbus Park on the city’s west side.”<<<Read More>>>

Information available from Cook County, Illinois Coyote Project

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PA House Passes Bill to Establish Coyote Bounty

HARRISBURG – The state House on Wednesday passed a bill authorizing the Pennsylvania Game Commission to set a bounty on coyotes.

The bill, approved by a vote of 111-78, would establish a “coyote incentive program” by offering $25 for coyotes killed in the commonwealth. It’s the first such bounty offered on a wild animal in 50 years.<<<Read More>>>

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Wolves in Maine in the 1600s – Part II

Part I
Part II
Part III
Part IV
Part V
Part VI

As I wend my way through the book, Early Maine Wildlife – Historical Accounts of Canada lynx, Moose, Mountain Lion, White-Tailed Deer, Wolverine, Wolves, and Woodland Caribou, 1603 – 1930 – by William B. Krohn and Christopher L. Hoving, I found some rather bizarre, yet fascinating writings that I would sooner categorize as tall tales and damned lies, than I would give much credence to actual historic events. However, I am willing to keep an open mind.

The original recordings were done in 1674 by a John Josselyn, found in Colonial Traveler: A Critical Edition of Two Voyages to New England. The authors of this book, Early Maine Wildlife, point out that Josselyn may have been confused by his use of terminology of the creatures he witnessed. For example, in the very first paragraph, Josselyn describes what he believes to be a “Jaccal” (jackal), which according to earlier European accounts and those of the American Indian, a jackal was commonly referred to as a coyote. So, this “Creature much like a Fox, but smaller”, we might only guess – wolverine?, muskrat?, bobcat?

The authors also warn their readers that Josselyn’s “terminology sometimes is misleading and his descriptions frequently fantastic”; or a kind way of saying the guy was mostly a damned liar and wild storyteller, as you will see in the below account.

Which brings us to his accounting of wolves he dealt with in his travels throughout Maine and probably parts of New England. As you will see, as you begin to read, the spelling is atrocious, the sentence structure abysmal and it all makes it difficult to comprehend and follow, but enough to realize how outlandish his story is. I did the best I could to present it exactly as it was presented in the book.

I’d call it tall tales and damned lies and laugh exceedingly over it as great entertainment.

~~~~~

Jaccals there be abundance, which is a Creature much like a Fox, but smaller, they are very frequent in Palestina, or the Holy-land.

The Wolf seeketh to his mate and goes clicketing at the same season with Foxes, and bring forth their whelps as they do, but their kennels are under thick bushes by great Trees in remote places by the swamps, he is to be hunted as the Fox from Holy-rood day till the Annunciation. But there they have a quicker way to destroy them. See New England’s rarities [footnote omitted]. They commonly go in routs, a rout of Wolves is 12 or more, sometimes by couples. In 1664, we found a Wolf asleep in a small dry swamp under an Oake, a great mastiff which we had with us seized upon him, and held him until we had a rope about his neck, by which we brought him home, and tying him to a stake we bated him with smaller Doggs, and had excellent sport; but his hinder legg being broken, they knockt out his brains. Sometime before this we had an excellent course after a single Wolf upon the hard sands of the Sea-side at low water for a mile or two, at last we lost our doggs, it being (as the Lancashire people phrase it) twilight, that is almost dark, and went beyond them, for the mastiff-bitch had seized upon the Wolf being gotten into the Sea, and there held him until one went in and led him out, the bitch keeping her hold until they had tied his leggs, and so carried him home like a Calf upon a staff between two men; being brought into the house they unbound him and set him upon his leggs, he not offering in the lease to bite, or so much as to shew his teeth, but clapping his stern betwixt his leggs, and leering towards the door would willingly have had his liberty, but they served him as they did the other, knockt his brains out, for our doggs were not then in the condition to bait him; their eyes shine by night as a Lanthorn: the Fangs of a Wolf hung about children’s necks keep them from frighting, and a very good to rub their gums with when they are breeding of Teeth, the gall of a Wolf is soveraign for swelling of the sinews; the fiants or dung of a Wolf drunk with white wine helpeth the Collick.

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