Are ravens ravishing greater sage-grouse populations?

sdfg
Greater sage-grouse might have a better shot at recovering if raven populations are controlled. Photo courtesy USGS.

Study shows link between cattle grazing, ravens and greater sage-grouse

Staff Report

As a generalist species that can take advantage of ecosystem disturbances, raven numbers have tripled across the West in the last few decades, and a new study shows that they are  almost fifty percent more likely to use sagebrush habitat if cattle are present.

And that’s not all — according to the research, published in Ecosphere, ravens will set up camp near greater sage-grouse breeding areas, where the big black birds prey on the eggs and chicks of the endangered sage-grouse. Since predation is the main cause of sage-grouse nest failure, the researchers suggest that  reducing ravens access to food and water could help with sage-grouse conservation.

The study was done by U.S. Geological Survey and Idaho State University scientists who looked at the relationship between common ravens and livestock across about 400 square miles of sagebrush-steppe ecosystem in southeastern Idaho.

“Common ravens are a known predator of numerous species including the greater sage-grouse,” said lead author and USGS scientist Peter Coates. “This study provides information to help rangeland resource managers develop conservation actions that focus on increasing the reproductive success of greater sage-grouse,” Coates said.

For example, limiting raven access to livestock resources, such as water troughs, and adjusting the timing of livestock access to sage-grouse breeding areas during the spring, would likely reduce raven predation on sage-grouse eggs.”

Research findings include:

  • The probability of raven occurrence increased by 45.8 percent in areas where cattle were present.
  • Ravens preferentially selected areas near sage-grouse breeding grounds, called leks, especially at sites where cattle were present.
  • Landscape characteristics also influenced raven occurrence. For example, ravens selected relatively open (fewer trees) low elevation areas, specifically those with cropland, wet meadow and urbanization. 

The study was a partnership of the USGS, Idaho State University, and Idaho Department of Fish and Game. The journal article is available here. Additional project information can be found at the USGS Western Ecological Research Center website.

Advertisements

4 thoughts on “Are ravens ravishing greater sage-grouse populations?

  1. Perhaps it would be a good idea to allow limited hunting during the sage grouse mating season. During my field work, I have observed that once disturbed, a group of ravens will move a considerable distance to eliminate the threat posed by your presence. Taking a few in the area of grouse leks could very easily provide the necessary protection without damage to the species as a whole. Study and analysis can provide a solution to many conservation issues of this nature. Personally, I can easily carry a shotgun in the boot, know exactly where the leks are, and would consider it an extraordinary challenge to take one of these birds considering their intelligence and superb eyesight. Open season? No way. Carefully designed plan for conservation? Absolutely, how we go about it is the key to a successful management program.
    PS: As a young boy I tried for decades to shoot a magpie, crow, or raven. I never hit a single one. Don’t cry for these poor innocent birds, they do a lot of damage in certain environments and are extremely smart and mobile. Conservation is best accomplished by science, not emotional response.

  2. The ravens are protected by Federal law. Why blame the raven when we do not follow sagegrouse management guidelines ? We could start with not grazing during sagegrouse nesting season. Manage for the suggested native grass cover and height guidelines. I have only found nests in late succession, high quiality plant communities, so manage for these. We do not have a raven problem we have a cattle problem.

    1. Kevin, I think that’s exactly what this study was trying to point out — that the ravens tend to multiply in cattle-grazing areas, thus becoming a problem for greater sage-grouse.

    2. Perhaps hunting, or, as the researchers suggest, making sure that cattle-grazing doesn’t make an area more attractive for ravens, by limiting water supplies, although if you have cattle, you gotta have water.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s