Sage-Grouse and Predator Prey Relations
After years of hue and cry, and being carpet-bombed with lawsuits, last March the U.S. Fish and Wildlife Service placed the greater sage-grouse on the candidate species list [here]. That didn’t halt the lawsuits, however [here, here].
The gist of the argle-bargle is that sage-grouse are in decline because their habitat is diminishing [here].
Nothing could be further from the truth. Sage-grouse population changes are governed by predator-prey relations, not habitat.
Sage-grouse do not eat sagebrush. They eat insects and seeds. They feed their chicks caterpillars. The insects and caterpillars that make up their diet also do not eat sagebrush. Principally, sage-grouse prey eat grass.
Sage-grouse can survive and even flourish where there is no sagebrush at all.
Sage-grouse, in turn, are prey to ravens, coyotes, cougars, eagles, hawks and other predators higher up the food chain. Sagebrush does not protect sage-grouse from their predators.
We reported these wildlife biology facts a year ago [here].
In a remarkable about-face, researchers have determined that sage grouse are NOT limited by “loss of habitat.” It turns out that sage grouse populations are governed by PREDATOR-PREY RELATIONS, just like all other animals. …
Idaho State University researchers found that ravens and badgers eat grouse eggs [here], but not ground squirrels. The clever scientists set up webcams near grouse nests and WATCHED as wild predators gobbled pre-hatched chicks. …
Real science, which is mainly concerned with reality, presents strong evidence that PREDATOR-PREY RELATIONS have everything to do with population dynamics, and that “loss of habitat” is a pile of bird crap.
That message has been lost on the general public, which has been pepper-sprayed with junk science regarding sage-grouse. Ranchers who live with sage-grouse are not fools, however, and know perfectly well that cattle and sage-grouse co-exist quite nicely. A recent news article demonstrates this verity:
Expanding the grouse conversation
By Nate Poppino, Magic Valley Times-News, May 13, 2010 [here]
BURLEY — As a rancher, David Andreason thinks the government’s not focused on the right ways to recover the greater sage grouse.
What about the effect of predators like coyotes and ravens, he asks? And why isn’t grazing used more to fight wildfires?
“Are we dealing with real issues, or are we chasing our tails with these feel-good ideas?” Andreason asked state wildlife officials Tuesday evening.
That perspective is exactly what those officials say is needed as they rebuild a working group focused on helping grouse in the southeast Magic Valley.
The South Magic Valley collaborative group is one of several across southern Idaho having problems keeping its non-agency members. The problem, said Mike Todd with the Idaho Department of Fish and Game, is that state and federal government representatives attend as part of their jobs, while private citizens have to make time themselves.
“It’s come down to nothing but a bunch of bureaucrats agreeing with each other,” Todd said. “We’re struggling. … This is a monumental effort.”
A meeting to find new members at the Best Western Burley Inn and Convention Center drew at least 20 people, including government representatives, ranchers and state Rep. Bert Stevenson, R-Rupert, Todd and Don Kemner, Fish and Game’s state grouse coordinator, briefed the audience on grouse population trends across the Magic Valley over the past few decades and the threats the birds face today.
The grouse, long in decline, is now a candidate species for federal protection, ranking as worth being added to the endangered species list but less of a priority than many other pending listings.
Wildfire and human infrastructure, especially energy development, are the bird’s top threats across the West, Kemner said. Combined, those and other issues lead to habitat fragmentation, the biggest problem highlighted by federal biologists in March. … [more]
Federal “biologists” are fools, as is also amply demonstrated.
The science of population dynamics and predator-prey relations has been well-studied. New findings include chaos theory, but the basic reality that both predator and prey populations vary over time due to their interactions with each other is well-established, modeled, and understood [here].
There are nuances that the general public may not be aware of, such as optimal foraging theory [here], surplus killing [here], mobbing behavior [here], and apparent or predator meditated competition [here].
But the basic truth that predator-prey relations, not “habitat”, govern population dynamics ought to be burned into the brains of every wildlife biologist in the world.
When Federal “biologists” fail to grasp the concept, it is proof that they are incompetent at their discipline. When Federal judges fail to grasp the concept, it is proof that they should not meddle in science at all.
When wildlife agencies make “monumental efforts” and still fail to grasp the fundamental concepts of wildlife biology, it is proof that our system of wildlife management is a complete and utter failure.
by Mike L.
by Marion D
I count sage-grouse in the spring and it is obvious looking at piles of feathers near the leks that predators have been visiting and dining on grouse. Enviros do not want to hear that though. They have their agenda and that is all that matters.
by Melanie
Yes, predator/prey relationships play into population dynamics…but where on earth did you get the idea that sage-grouse do not eat sagebrush and that they don’t need it??? They DO in fact eat sagebrush, it is their primary winter food and this has been well-studied…look at the literature. They also eat insects, especially during the spring months. You can tell by breaking open their scat whether they have been eating sagebrush or insects. They use sagebrush for nesting and cover. However, there are several grouse species…so maybe you have a different one in mind! READ THE SCIENTIFIC LITERATURE!
Dear Melanie,
You are quite wrong. If you know of some paper that contends that sage grouse eat sage brush, please share it with us. Because they don’t, you know.
IF YOU ARE GOING TO SHOUT AT US WITH ALL CAPS, THEN MAYBE YOU SHOULD PROVIDE SOME DOCUMENTED EVIDENCE TO BACK UP YOUR CLAIMS. OTHERWISE YOU ARE JUST CONSUMING ELECTRONS USELESSLY.
Mike
Biologists do not want to talk about sage-grouse nests being destroyed by hoards of ravens. Habitat is NOT the key to everything!! Predator/prey relationships are key.