Study Area
Uncompahgre Plateau 

Project Status
Completed, 2005

Research Objectives

• To evaluate the importance of habitat quality on mule deer population dynamics.
• To determine management priorities to reverse mule deer population declines.

Project Description

In the 1990s, mule deer populations began to decline across the western United States. CPW researchers set out to identify reasons for the decline, focusing on those factors that could be controlled through management efforts. Researchers recognized both habitat quality and predation as possible factors, but did not know which one played a larger role in mule deer population declines. 

To evaluate habitat as a limiting factor, researchers measured the effect of habitat enhancements on mule deer survival and fawn recruitment during a six-year study. 

During the winter months, researchers artificially enhanced habitat quality by distributing feed supplement pellets around the study area to improve deer nutrition. Predation levels were left unchanged. Researchers then measured pregnancy rates, doe body condition, and doe and fawn survival rates in the supplemented area and in an un-supplemented control area. Halfway through the study, the treatment and control areas were reversed in a crossover design.

Fawn survival in the supplemented area was significantly greater than in the control area during the winter, which resulted in a positive rate of population increase. These results provided clear evidence that nutrition and habitat quality were important factors contributing to deer population declines. 

This CPW project aligned with a research project conducted by the Idaho Fish and Game Department, which found that predator control had a smaller positive effect on declining mule deer populations.

Although completed in 2005, this project still serves as a reference and basis for many of CPW's current research projects. This project also helped wildlife managers determine factors that could be managed to reverse mule deer population declines.

Resources

​​​West Slope Mule Deer Strategy​

Bishop, Chad J. and Gary C. White. 2001-2006. Effect of nutrition and habitat enhancements on mule deer recruitment and survival rates. Colorado Division of Wildlife. (Compiled progress reports from a Federal Aid project).

Mule deer​ populations in Colorado have shown dramatic fluctuations since the 1960s. Beginning in the 1990s, some western Colorado mule deer herds demonstrated the most recent decline. As such, CPW focused research efforts on developing management techniques to increase the health and survival of mule deer, an economically and ecologically important game animal. 

Mule Deer Research Projects:

• Mitigating Impacts of Energy Development on Mule Deer Populations
• Effects of Habitat Treatments on Mule Deer Survival and Health During the winter
• Impact of Habitat Quality on Mule Deer Reproduction and Survival

Lynx Research Projects:

• Evaluating Options to Monitor Canada Lynx Reintroduction in Colorado
• Mammal and Breeding Bird Response to Bark Beetle Outbreaks

Study Area
Statewide

Project Status
Completed

Research Objective:
To determine how bark beetle outbreaks have impacted breeding birds and mammals in Colorado.

Wildlife Cameras

As part of a project to learn about the impacts of bark beetle outbreaks on wildlife, Colorado Parks and Wildlife deployed 300 remote wildlife cameras at randomly selected locations throughout spruce/fir and lodgepole pine forests in Colorado.  To the right are samples of the almost 400,000 photos collected from the project.

Project Description

Since 1996, millions of acres of Colorado forests have fallen victim to bark beetle infestations. This unusual epidemic has left researchers wondering how local wildlife living in these forests will respond.

This study will focus on tracking how mammals and breeding birds alter their use of subalpine forests during the course of an outbreak. 

Researchers expect wildlife response to the beetle epidemic to vary by species and forest system. Some species may stay in the area during the full course of the outbreak, while others may disappear once the area is infected. For example, researchers expect red squirrel use of lodgepole pine forests to decrease as the outbreak affects cone-producing trees, which serve as the squirrel's primary food source. 

The focal species for this study are those listed as a priority species under the Colorado Wildlife Action Plan and/or listed as sensitive species by the United State Forest Service Region 2 and/or listed as vulnerable at the sub-national scale by NatureServ. 

These species include:

• American marten
• American Three-toed Woodpecker
• Broad-tailed Hummingbird
• Cassin's Finch
• Cordilleran Flycatcher
• Dusky Flycatcher
• Dusky Grouse
• Evening Grosbeak
• Northern Goshawk
• Olive-sided Flycatcher
• Red Crossbill
• Red-naped Sapsucker
• Williamson's Sapsucker

Two additional species, the snowshoe hare and red squirrel, are focal species as well because together they compromise nearly 100 percent of the diet of the Canada lynx, which is a state and federally listed species.  

Researchers plan to survey the selected mammal species using motion-sensor cameras. Bird species will be surveyed during early morning counts throughout the breeding season (late May to early July). Because the survey methods are general, researchers should be able to gather information about variety of additional game and non-game species beyond those species of concern listed above. Researchers will use this data to determine which species decrease their use of these forests as bark beetle infestations run their course, which species increase their use, and which species are unaffected.

Associated Publications

Ivan, J. S. 2013. Small mammal and breeding bird response to bark beetle outbreaks in Colorado. Pages 1-13 in Wildlife Research Report, Mammals Research Program, Colorado Division of Parks and Wildlife, Fort Collins, CO. 310 pp.

Study Area
Statewide

Project Status
Ongoing

Research Objectives

• To evaluate options to monitor the long-term success of lynx reintroduction efforts.

Project Description

In 1997, Colorado Parks and Wildlife began a large-scale effort to reintroduce lynx into the state with the goal of establishing a self-sustaining population of lynx. Four years after the last lynx was released into the state in 2006, CPW deemed the initial lynx introduction effort a success. Research focus has now shifted towards determining the long-term success of the reintroduction. 

Researchers cannot use traditional methods to estimate abundance of lynx populations because the animals move extensively, exist at low densities, and can be difficult to capture. Instead, this project aims to monitor lynx population trends by using presence/absence data to estimate the proportion of the landscape occupied by lynx.  This proportion should trend up or down as lynx abundance moves up or down.

From 2009 to 2010, researchers tried various methods of detecting lynx in areas where they were known to be present. This work showed that snowtracking surveys conducted by snowmobile were the most efficient means to detect lynx. However, such surveys can only occur in roaded areas. For surveys in wilderness areas, researchers determined that remotely triggered wildlife cameras were the most efficient method for detecting lynx. 

Based on data collected from field research in 2009-2010, researchers determined that a sample of 50 sample units would need to be surveyed annually in the San Juan and South San Juan Mountains in order to be able to detect meaningful trends in lynx occupancy in the region. 

Work will be completed by CPW in partnership with the U.S. Forest Service. Additionally, other ranges throughout the state will be surveyed on a rotating basis such that when the monitoring effort is at full strength, annual data will be collected in the Southwest to monitor trends in the population, and periodic surveys will be conducted elsewhere to determine the extent of the population in the state.  

Associated Publications

• Ivan, J. S., 2013. Statewide Monitoring of Canada lynx in Colorado: Evaluation of options. Pages 15-27 in Wildlife Research Report, Mammals Research Program, Colorado Division of Parks and Wildlife, Fort Collins, CO. 310 pp.
• Ivan, J. S., 2012. Monitoring Canada Lynx in Colorado Using Occupancy Estimation: Initial Implementation in the Core Lynx Research Area. Pages 26-34 in Wildlife Research Report, Mammals Research Program, Colorado Division of Parks and Wildlife, Fort Collins, CO. 195 pp.
• Ivan, J.S., 2011. Monitoring Canada Lynx in Colorado Using Occupancy Estimation: Initial Implementation in the Core Lynx Research Area. Wildlife Research Report, Mammals Research program, Colorado Division of Parks and Wildlife, Fort Collins, CO.

Study Area
Field data are being collected near Durango, CO

Project Status
Completed 2018

Research Objectives

• To determine the influence of urban environments on black bear behavior and population trends.
• To test management strategies for reducing bear-human conflicts.
• To examine public attitudes and behaviors related to bear-human encounters.
• To develop population and habitat models to monitor and manage bears.

Project Description­­

Black bear-human encounters and conflicts are increasing in Colorado and across the country. This trend is likely to continue as residential development expands and changes in weather (such as more frequent droughts) reduce the availability of natural foods for bears. Bear-human conflicts commonly result in property damage, threats to public safety, rising wildlife management costs, and high bear mortality.

Despite these consequences, the scientific community does not know if increases in conflicts reflect changes in the number of bears or a behavioral shift to eating human food resources or a combination of both. Without a thorough understanding of the relationship between conflict rates, bear behavior and population dynamics, wildlife agencies cannot successfully reduce conflicts through management.

A statewide increase in bear-human encounters and conflicts is a high priority management issue for Colorado Parks and Wildlife (CPW). As a result, CPW initiated a comprehensive, five-year research project to identify factors responsible for rising conflicts and to test management strategies to reduce those conflicts in the future. Most of the data for this project was collected in the vicinity of Durango, Colorado, but regional and statewide information was also used to meet project objectives.

To meet project objectives, the research staff conducted the following field research activities:

• Trapped and collared black bears in the urban-wildland interface around Durango.
• Tracked bear movements and feeding patterns using global position system (GPS) satellite collars.
• Monitored bear survival and reproduction using data from the GPS collars and by visiting winter dens of adult females.
• Collected data on the availability of summer and fall natural foods for bears, which largely includes nuts and berries from gambel oak, serviceberry, chokecherry, hawthorn, and pinon pine.
• Employed non-invasive genetic surveys to estimate the bear density and population size around Durango and at a nearby wildland site.
• Tested wide-scale urban use of bear-resistant garbage containers for their effectiveness in reducing bear-human conflicts.
• Surveyed the public on attitudes and perceptions related to bears, bear-human conflicts, bear management, and motivations to reduce interactions with bears.

Reports
Annual progress reports 2010-2018