Researcher studies increased predation of sagebrush songbirds in natural gas fields

December 14, 2016

Arid land bird populations are in decline around the vicinity of oil and gas wells in Wyoming -- but, not for the reasons you might initially think.

While such development has encroached on and hindered nesting habitat for three types of sagebrush-obligate birds, predation of these birds has increased because rodent populations in the vicinity of oil and gas wells have increased, which has, in turn, increased nest predation.

Anna Chalfoun, a University of Wyoming associate professor in the Department of Zoology and Physiology, and assistant unit leader of the Wyoming Cooperative Fish and Wildlife Unit, and her graduate students have been studying and collecting data about three species -- the Brewer's sparrow, sagebrush sparrow and sage thrasher -- in Wyoming for seven years. These birds use sagebrush for cover to build their nests on the ground or low to the ground within the sagebrush.

The study, which began seven years ago, has taken place at six sites in Jonah Field and six more at the Pinedale Anticline in western Wyoming.

"We found the majority of nest predators at the nests are rodents. Rodents are more abundant where there is natural gas development," Chalfoun says. "We tested the hypothesis that rodents were more abundant surrounding gas fields because their main predators (raptors, coyotes and badgers) avoided gas fields, but our data did not support this idea."

vLindsey Sanders, a UW master's student in zoology and physiology from Boulder Creek, Calif., conducted work on the above hypothesis, Chalfoun says.

Besides mice, these rodents include two species of squirrels -- Uinta ground squirrels and the 13-striped ground squirrel. "We are now continuing to try to figure out why the rodents are in the natural gas development areas where there is (nesting) habitat loss," Chalfoun says. "We are seeing more rodents. We are not sure why they are drawn to those areas. Another hypothesis is that they are receiving food subsidies from the sometimes novel types of plants that establish in the reclaimed areas surrounding well pads and along pipeline scars."

The study's findings show:

From 2011-16, 93 percent of predation to Brewer's sparrows was caused by rodents. Of 44 predation events captured on infrared video camera, 24 were by deer mice. Chipmunks accounted for 11 nest deaths, while ground squirrels were responsible for six casualties. The loggerhead shrike, a type of bird, was responsible for the other three deaths.

During the same time period, 60 percent of predation of 23 sage thrasher nest depredations caught on camera was caused by rodents, including deer mice (eight), chipmunks (eight) and ground squirrels (four). Badgers were responsible for six deaths and magpies two. A raccoon, loggerhead shrike, American kestrel, short-eared owl and northern harrier each accounted for one death.

"I get jazzed to know what's going on," she says. "The mice are so aggressive. They sometimes suffocate and take the nestlings out one at a time. We've found the majority of nest predators at the nests are rodents.

"We started this because state and federal agencies, such as the Wyoming Game and Fish Department, and the U.S. Geological Survey, were interested in the effects of habitat change on nongame species of wildlife," she says.v
-end-


University of Wyoming

Related Predators Articles from Brightsurf:

Boo! How do mexican cavefish escape predators?
When startled, do all fish respond the same way? A few fish, like Mexican cavefish, have evolved in unique environments without any predators.

Herbivores, not predators, most at risk of extinction
One million years ago, the extinction of large-bodied plant-eaters changed the trajectory of life on Earth.

Bugs resort to several colours to protect themselves from predators
New research has revealed for the first time that shield bugs use a variety of colours throughout their lives to avoid predators.

Jellyfish contain no calories, so why do they still attract predators?
New study shows that jellyfish are an important food source for many animals.

'Matador' guppies trick predators
Trinidadian guppies behave like matadors, focusing a predator's point of attack before dodging away at the last moment, new research shows.

The European viper uses cloak-and-dazzle to escape predators
Research of the University of Jyväskylä demonstrates that the characteristic zig-zag pattern on a viper's back performs opposing functions during a predation event.

Predators help prey adapt to an uncertain future
What effect does extinction of species have on the evolution of surviving species?

To warn or to hide from predators?: New computer simulation provides answers
Some toxic animals are bright to warn predators from attacking them, and some hide the warning colors, showing them only at the very last moment when they are about to be attacked.

Dragonflies are efficient predators
A study led by the University of Turku, Finland, has found that small, fiercely predatory damselflies catch and eat hundreds of thousands of insects during a single summer -- in an area surrounding just a single pond.

Predators to spare
In 2014, a disease of epidemic proportions gripped the West Coast of the US.

Read More: Predators News and Predators Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.