Awakening to the spirit and beauty of the northern Great Plains
Friday, January 15, 2010
Coyote data (or Coyotes per party hour)
If the coyote is now our top wild mammalian predator in grassland (I find myself wondering if I am forgetting one, but no, the wolf and grizzly are both gone for now), then according to some studies, it is an important player on the stage of our ever-diminishing grassland biodiversity. Ecologists who speak of the detrimental effects of a “mesopredator release” that occurs once you remove the top or “apex” predator, may point to the coyote as a mesopredator itself, which, after the loss of the plains wolf, has increased and perhaps diminished some of the prey species (bird and small mammal), while others may describe the red fox as the real mesopredator that was released in grassland ecosystems when the coyote was persecuted in the 1960s after the advent of snowmobile hunting. [For a look at the Apex predator/mesopredator story see: BioScience, October 2009, Vol. 59, No. 9, Pages 779–791, here is an abstract; and Finley J.K. 2006. The rise and fall of the Red Fox beneath the apex of Palliser’s Triangle. Blue Jay 64(3): 155 - 159 and Finley, J.K. 2005. The fox that stole the apex of Palliser’s Triangle: a correction. Blue Jay 63(3) : 135-138]
I don’t pretend to know whether the whole apex predator/mesopredator release theory holds any water (though it sounds pretty good) and certainly can’t guess what the net effect has been of wolves disappearing, coyotes thriving, then thinning out for a few decades only to surge again recently in an inverse relationship with the red fox population. Even so, it would seem reasonable to say that grassland ecologists should look into the matter--and our policies on coyote depredation adjusted accordingly.
As it is, we have provincial governments like ours in Saskatchewan establishing bounties without any science to (a) show that coyote populations are “too high,” whatever that means, and (b) determine the local ecological effects of killing large numbers of coyotes. In fact, the provincial government does not seem to know how many coyotes we have in the province; nor have they shown us data demonstrating that coyote numbers are rising.
Nature Saskatchewan, however, does have data on coyote population trends. As the province’s long-standing organization of field naturalists, we have conducted mammal counts in conjunction with the Christmas Bird Counts each winter. The data is gathered by volunteers recording sightings of mammals and mammal sign using standardized methods. “Coyotes per party hour” may sound like something that should be happening at a bar in Maple Creek but it refers to the way the data is analyzed to give it some value in showing trends in populations. Each group of naturalists out there driving, snowshoeing, skiing or walking in their count circle for a day is one “party” and they submit their results along with the number of hours they recorded data—hence coyotes per party hour.
So, what does the Nature Saskatchewan data show? Today, Alan Smith, a Nature Sask volunteer and retired Canadian Wildlife Service biologist who compiles and reports the count data, sent me a spreadsheet with the data on coyotes from 1980 to 2008. It shows that coyote numbers have in fact been declining from 2001 to 2008—from a 28 year high of .25 coyotes per party hour in 2001 down to .10 in 2006 and recovering slightly to .18 in 2008. It also shows that coyotes did increase from 1980 to 2001; however, that may have been a recovery to normal levels in the absence of poison and other forms of persecution in the previous decades. Regardless, there is nothing in the data to show that we are suddenly being over-run by coyotes.
So we do have some data on coyotes, and none of it justifies a bounty. But maybe the coyotes are getting more aggressive and killing more lambs and calves—which is what some producers are saying. In that case--even though there is no data to demonstrate such a trend--perhaps we need to help producers find ways to discourage or eliminate the problem coyotes that are exhibiting this behaviour, not kill every coyote a bored plinker can spot from the cab of his pickup. Then there is the posibility of compensating producers with predation insurance programs. If hail destroys a farmer's crops, his insurance compensates him. Couldn't the same be done for the lambs and calves lost to predators?
Older and wiser ranchers will tell you it’s a bad idea to kill the coyotes you have on your range if they aren’t coming near your livestock, because removing them is an invitation to other coyotes that may be much more aggressive. Most coyotes live on mice, gophers and other small prey, not to mention a fair amount of vegetable material. It doesn't seem fair to paint them all with the same brush--particularly the red brush being used every day this winter in Saskatchewan's Rural Municipality offices to mark their severed paws under this bounty.