Norm Bishop sent me some excellent communication from Doug Smith(Yellowstone Wolf Studies) and John Byers U. Of Idaho) discussing what we reported on the other day about the North Dakota Pronghorn population downward spiral(severe winter weather blamed)...............As Norm notes,,,,,,,we know that coyotes inhabit North Dakota and likely take a fair share of pronghorn calves out of the population......... In Yellowstone, we know that wolves decrease the coyote population and that as a result, there is less coyote predation on pronghorn..................If North Dakota Game Officials were "thinking like a mountain", they would restore wolves to their landscapes, which would likely help to some degree mitigate the pronghorn losses that are incurred by the cold winter weather

The following note is personal communication from Doug Smith, who, with John Byers, observed that wolves appeared to benefit pronghorns by excluding coyotes from wolf  den sites and central territories.  Perhaps they would benefit North Dakota pronghorn populations as well, if coyotes are taking anywhere near the percentage of newborns as they were on Yellowstone's northern elk range pre-wolf.  Just another response to the question, "What good are wolves?"

---------- Forwarded message ----------
From: Norman Bishop <nabishop@q.com>
Date: Fri, Oct 21, 2011 at 7:31 PM
Subject: North Dakota's pronghorns declining?
To: Rick Meril <rick.meril@gmail.com>

Norm B.

John  A. Byers, University of Idaho, and Douglas W. Smith, Yellowstone Center for Resources,  studied how wolves improve pronghorn fawn survival in Yellowstone.

(The pronghorn population in northern Yellowstone has been declining for decades.  I recall data from Doug Scott that coyotes were killing more than 95% of the fawns.)

Pronghorn female fecundity, and litter size (2) was comparable to other healthy pronghorn populations, and the condition of young was good.  But the median age of death was 6 days in areas where coyotes are a major source of mortality.  Some pronghorn females gave birth on winter range (near Gardiner), while others migrated 20 miles to high elevation grasslands before giving birth.  Less than 1% of fawns born on winter range survived, while 11% of those born elsewhere survived.  These differences appeared to be related to the relative density of wolves.  Wolves are intolerant of coyotes, and have reduced them by more than 50% in high elevation grasslands.

These results offer support to the mesopredator release hypothesis, and suggest that the prime cause of low pronghorn recruitment in North America has been the extirpation of wolves and the subsequent increas in the density of the mesopredator, the coyote.

The mesopredator release hypothesis predicts that the largest predator in a multipredator  system will exert a cascading series of effects on smaller predators and on prey.  When the top predator is present , the density of smaller predators (mesopredators) is reduced, with a concomitant increase in the density of the mesopredator's prey.  When the top predator is absent, the mesopredator is released from control, increases in density, and reduces the density of its prey.

Some 93% of all pronghorn fawns studied were dead before the end of August.  Nearly all fawns born on winter range died, while 16% of those born in Lamar Valley survived.  The presence of wolves in Lamar enhanced fawn survival, and there was a linear relationship between wolf density and probability of fawn survival.

On the winter range,  where there were no wolves, Byers and Smith saw 99% fawn mortality.  They saw coyotes frequently, they saw coyotes kill fawns twice, they found 4 ear transmitters from winter range fawns at coyote dens, and found scratches from coyote teeth on other ear transmitters.  They saw one pronghorn female killed the day after she gave birth, and circumstantial evidence suggests 5 other mothers on winter range died in this way in 2000.

In the 18th and 19th centuries, pronghorn were at high density in the grassland of North America, but pronghorn annual recruitment is low now, because of high coyote numbers.  Wolves represent the best chance for survival of Yellowstone's indigenous pronghorn population.