The Top Dog Returns: The Impact of Wolves in the American West
Gray wolves are naturally recolonizing Washington State, offering a rare opportunity to study ecosystem responses when a top predator returns.
A gray wolf photographed by a stationary camera in our study area in the Okanogan Highlands of Washington.
For the last two winters our team has been placing animal-borne cameras and global positioning system (GPS) collars on white-tailed deer and mule deer to monitor how these prey species are responding to the arrival of wolves. So far, we have placed cameras on 48 deer and GPS collars on 43 deer. To capture the deer we have been using cage traps, but our capture rates are low, with one deer being caught every 2-3 days.
Example of the cage traps we have been using to capture deer.
Last winter we tried capturing deer using a specialized method from a helicopter. We caught 15 deer in one day. The capture process was quick, with the deer being safely released after about 20 minutes of processing. It would have taken us a month of work on the ground to capture the same amount of deer.
Aerial capture of animals is being increasingly used by researchers.
We have been successful in generating enough funding to continue capturing deer using the cage traps on the ground. But our goal is to capture another 280 deer over the next few winters using the aerial capture methodology.
You can help us achieve our goal by donating to our crowdfunding campaign.
We are seeking to raise $12,000 to assist with the costs of aerial capturing deer this coming winter.
If we exceed our funding goal it will provide us with additional resources for our broader project that is examining how the return of the wolf to the American west reshapes the environment. For example, if we exceed our target, additional funds will be used to purchase GPS collars for other predators such coyotes, cougars, black bears.
We look forward to working with you to achieve our goal.
If you are interested in learning more about our project some information is provided below.
Researchers (left to right) Apryle Craig; Thomas Newsome, PhD; Justin Dellinger; Aaron Wirsing, PhD; Carolyn Shores.
Large carnivore populations have collapsed worldwide because of human persecution and habitat loss. The resulting lack of top predators in many areas has affected smaller predator populations, their prey and even vegetation.
However, gray wolves are now naturally recolonizing many areas of the United States following their reintroduction into Yellowstone National Park and surrounding areas in 1995 and 1996.
This offers a rare opportunity to study ecosystem responses when a top predator returns.
For example, since 2008, fourteen wolf packs have been established in Washington State after an absence of 80 years, but much potential wolf habitat remains unclaimed. This scenario creates patchiness in wolf distribution that allows for a natural experiment to test whether and how the return of this “top dog” to the American west reshapes the environment.
Our project is primarily focusing on the impacts of wolves to the hub of the food web in this ecosystem: white-tailed deer and mule deer.
These two species are crucial prey for other North American carnivores such as cougars, coyotes and black bears. Given their abundance, broad distribution, and varied diets, mule and white-tailed deer are also ecologically influential grazers in the American west.
Finally, these deer are economically important as both game species and competitors with livestock. Consequently, our findings will be of great relevance to carnivore conservation, habitat management, hunting and agriculture.
White-tailed deer (left) and mule deer (right).
What Distinguishes Our Project From Other Wolf Studies
Our project is unique in that Washington’s wolves are not occupying protected areas or wilderness, where the majority of previous wolf research has been conducted.
Rather, the wolves have established territories in regions that are also used and managed by humans. Consequently, the return of wolves to Washington offers a rare and exciting opportunity to ask whether the ecosystem effects of top predators already documented in parks and preserves such as Yellowstone National Park also occur in areas that are shared with people.
Furthermore, most previous research on wolves in the United States has focused on interactions between wolves and elk or moose. Little is known about interactions between wolves and white-tailed deer or mule deer.
Sharing Our Findings
Our findings will be widely shared with the public through a research website, presentations at local schools, community centers and wildlife management agencies, television shows, newspaper articles, and scientific publications and presentations.
In fact, our research has already resulted in a television show titled “Wolves and the Ecology of Fear” produced by the Public Broadcasting System (PBS).
Click here to watch the video
Who We Are
We are a collaborative international team of researchers from the University of Washington, Oregon State University, Florida International University, the University of Sydney, and the University of Maryland.
In 2012, we joined forces to better understand the ecological roles played by top predators like wolves.
We have focused our research on Washington’s wolves because the patchy distribution of this top predator in the Pacific Northwest offers the rare chance to track ecosystem changes in areas with wolves in comparison to nearby sites that have yet to be recolonized.
Where We Work
Our study is located in the Okanogan Highlands of northeastern Washington, where the Strawberry and Nc'icn wolf packs have settled. We have four study sites: two that are home to wolf packs and two control areas that have yet to be recolonized by wolves. The control areas will serve as baselines for establishing the magnitude of ecosystem changes in the wolf-impact sites.
Map showing the home range areas of wolves in our study area, plus our two control sites.
How We Conduct the Deer Research
To examine deer responses, we are collecting behavioral data using animal-borne cameras, global positioning system (GPS) collars and scat samples.
The video captured by the animal-borne cameras enables us to document food choices (we can watch every bite the deer take!) as well as reactions to the threat of wolves (e.g. how often the deer scan their surroundings for approaching predators).
The GPS collars do not provide video footage, but they allow us to track the movements of instrumented deer over the course of a year.
We can use locations from these collars to ask if deer avoid areas where they are likely to be attacked by wolves (valley bottoms) and if deer move to safety (into cover) when wolves are nearby.
Scat (aka poop) samples we collect provide us with another way of documenting deer diets. These samples could reveal that deer change their diets when confronted with wolf danger, possibly because they stop eating certain foods that are located in areas that are risky.
The animal-borne cameras provide an “animal’s eye view” of the environment and can be used to examine patterns of feeding, habitat use, and vigilance (i.e., looking out for predators).
Additional Research Topics
1. Mule Deer Fawn Survival: Our research team is interested in how wolves affect survival of mule deer. We are focusing specifically on this species because mule deer have declined throughout the western U.S. since the 1980’s. The cause for their decline is unknown, but it has generated concern in conservation, wildlife management and hunting communities, as the mule deer is an iconic symbol of the American West and an economically important species.
To study the impacts of wolves on mule deer populations, we are examining the survival of mule deer fawns in areas with and without wolves, because fawn survival drives population dynamics of deer species.
We are using expandable Very High Frequency (VHF) radio collars to determine fawn survival. These collars track the fawns’ location and alert us if a deer fawn dies, so we can quickly find the fawn and determine why it died.
Mule deer fawn fitted with an expandable collar.
2. Wolf and Coyote Interactions: We are also studying the response of one of the major predators of deer fawns - the coyote - to wolves. The coyote is a common, widespread smaller predator that expanded its range across the U.S as wolves were locally hunted to extinction. Wolves historically controlled coyote populations through competition and direct killing.
A coyote within our study area.
Now that the true ‘top dog’ is returning, the question remains if wolves can suppress coyote populations to historical levels and increase the survival of coyote prey species such as deer fawns. Importantly, coyotes are a major predator of deer fawns whereas wolves preferentially take adult deer.
Rise of the coyote: will wolves suppress coyotes as they return to the western U.S.?
To assess wolf-coyote interactions, we are comparing coyote population density and diet using a combination of scat and track surveys, and potentially GPS collars, in areas with and without wolves.
Scat samples will tell us whether other carnivores shift their diets in order to reduce competition with wolves, while also yielding DNA that can be used to generate population estimates.
By deploying GPS collars, we will be able to track the movements of other carnivores throughout the year and, consequently, ask if other carnivores change the way they use the landscape when in the presence of wolves.
Other carnivores we plan to study in this manner include cougars and black bears.
3. Wolves and Vegetation: To explore plant responses to wolf recolonization, we are establishing paired herbivory exclosures (deer fences) and control plots (no fencing) in wolf and non-wolf areas. We will measure plant characteristics including height, growth and species representation. Any differences between the exclosures and controls will reveal the impacts of feeding by deer. Collecting deer pellets in wolf and non-wolf areas will reveal differences in deer diet composition between wolf and non-wolf study areas. Our findings will inform the ongoing debate about whether wolves can indirectly affect plant communities by altering prey foraging behavior and help us to predict how Washington’s forest landscapes will change in the face of wolf recolonization.
Accomplishments So Far
In 2012, we received a grant from the National Science Foundation that has supported much of our work to date.
We are also supported by smaller grants and/or logistical help from the Confederated Tribes of the Colville, Conservation Northwest, Mule Deer Foundation, Safari Club International Foundation, Seattle City Light, Washington Department of Fish and Wildlife and United States Forest Service.
With our existing support, we have successfully completed field work for two winter field seasons (December through March of 2012-2013 and 2013-2014). This has included:
- Fitting wolves with radio-collars in collaboration with the Colville Fish and Wildlife Department.
- Deploying 25 white-tailed deer and 23 mule deer with animal-borne camera collars to record feeding behavior.
- Deploying 22 white-tailed deer and 21 mule deer with GPS collars to track year-round movements.
- Erecting four remote camera grids, one per study area, with each containing 16 stationary cameras for a total of 64 cameras.
- Delivering a series of presentations on this project to 8th grade environmental science classes in the Mercer Island School District and to undergraduates at the University of Washington.
- Collaborating with PBS to shoot a documentary on our work titled, “Wolves and the Ecology of Fear”.
The Next Steps
Over the next four years we are aiming to:
- Construct 240 herbivory exclosures (fences) to measure deer impacts to plants in wolf and non-wolf areas.
- Collect mule deer, white-tailed deer, coyote, wolf, cougar and black bear scats for diet composition analysis.
- Place animal-borne camera collars on 20 more white-tail and mule deer, respectively.
- Place GPS collars on 120 more white-tail and mule deer, respectively.
- Place GPS collars on 5 more wolves.
- Place GPS collars on 20 coyotes and cougars, respectively.
- Place 120 fawn survival collars on mule deer fawns.
- Survey coyote populations using scat surveys.
Some of our next steps will be funded by our existing grants. For example, our NSF grant will cover the establishment and monitoring of the deer exclosures, but we have yet to obtain the funds for other key steps.
In particular, we need your support to fund the aerial capture of deer for collar deployment during our upcoming winter field season (2014-2015). If we exceed our funding goal of $12,000 then it will provide us with additional resources for our project.
For example, a five dollar donation will help us to purchase DNA vials and other laboratory equipment. Larger donations will be used to purchase additional GPS collars for wolves and the other predators such coyotes, cougars, black bears.
For specific ideas about how your donations will contribute to our research effort you can view our impact items.
Thanks for your support!
One Week To Go!
Published on Friday, Nov. 7, 2014 at 04:36 PM (PDT)
Please help us to bring the effort home! Every donation counts.
An elk (perhaps looking out for wolves?) captured by one of our remote cameras.
Link to this Update
Nancy Warren National Wolfwatcher Coalition
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Make an Impact
GPS uploads for up-to-date information on animal locations via satellites, nitrile gloves for scat collection, or trap bait for a deer capture. These supplies allow us to analyze the impact of wolves on deer diet composition.
Scat sample analysis, one day of fuel to access remote sites, or video analysis of deer GPS collars.
Are wolves changing deer grazing patterns? Your contribution will purchase one vegetation exclosure fence to compare deer grazing habits in wolf and non-wolf areas.
Are wolves impacting fawn survival? Your contribution will help us answer this question by providing a deer fawn VHF collar to monitor fawn survival in wolf and non-wolf recolonized areas.
Deer collaring via aerial capture on a helicopter. Your contribution will allow us to quickly and safely catch and equip a deer with a GPS or animal-borne video camera collar.
GPS collars for deer, coyotes or cougars provide a breadth and depth of data on how wolves are affecting deer and other carnivores in the ecosystem. The data from these collars allow us to analyze if wolves are altering daily and seasonal movement patterns, amount of time spent eating, diet composition, and more.