Yukon North Slope Grizzly Bear Research Project
Organization Responsible
Ramona Maraj – Carnivore Biologist, Yukon Government
Molly Kirk – Biologist, Parks Canada
Dorothy Cooley – Regional Biologist, Yukon Government
Partner Organizations
Wildlife Management Advisory Council (North Slope)
Aklavik Hunters and Trappers Committee
Parks Canada, Western Arctic Field Unit
Yukon Government, Department of Environment
Program Description
25 GPS collars and 15 VHF collars will be deployed within the study area. 10 GPS and 15 VHF collars will be deployed in the first year of the study and 15 GPS collars will be deployed in the second year. We will use a rotary aircraft to search open areas for bears an/or fresh sign (tracks, scats, digs). While these search efforts will be limited to open habitats where grizzly bears and their tracks can be seen from the air, the majority of the study area is treeless. We will attempt to disperse search effort (search time per unit area) evenly throughout the study area. GPS collars will be placed on a random sample of males and females. VHF collars will be placed on females only. Family groups will not be excluded from collaring. Once a bear has been located we will use a Bell 206B helicopter for darting and capture. The capture crew will determine if the surrounding habitats and geography permit a safe pursuit and capture. Pursuit will be stopped when any target bear shows clear signs of fatigue (e.g., stumbling, tongue hanging out), and in all captures, chase times will be limited to as little time as possible (e.g., 2-3 minutes). Canadian Council on Animal Care (CCAC ) Guidelines will be followed to the best of our ability.
We will divide a subset of the study area systematically into 70 cells and place one baited hair snare site in each 7kmx7km cell. We will attempt to place the grid within the study area so that some bears have been collared off the grid, while others have been collared on the grid. We will trap each cell for five ten-day sessions, and move each capture site >1km after each check. (All bait sites will be at least 1 km apart.) We will begin installing sites when the snow has melted (June 15, 2005) and finished the third check by August 1, 2005. We will conduct the survey for two consecutive years (2005 and 2006) to capture some annual variation. We will select hair snare sites that have the best potential to catch a bear at the time of setting. We will use historical live capture success data from Nagy et al. (1983), habitat mapping, and observation information collected during concurrent live-capture, and subsequent radio telemetry to help us select the hair snare sites.
Methods for capturing hair from grizzly bears at bait sites have been presented by Woods et al. (1999). We will use liquid baits because they are easier and faster to install, and present less risk to the public because the potential to reward bears is removed. Liquid baits have been used for several other recent grizzly bear inventories with good capture success (Poole et al. 2001, Mowat and Strobeck 2000). We will pour 1 cup of fish oil (fish rotted to a liquid), 1 litre of rotted Alaska Fish Fertilizer and 2 liters of rotted blood or liquefied animal remains on wood or shrub matter piled up in the centre of each site (after Poole et al. 2001). We will introduce a novel scent in each session (e.g., beaver castor to each site during the second session, anise oil during the third session, and bear magnet during the fourth session). All hair from each barb will be collected with bare hands and stored in paper envelopes in a cool dry place.
Some traditional and local knowledge of grizzly bears and bear habitat in the area has already been gathered (Department of Resources, Wildlife, and Economic Development, in prep.). There are also some written records of traditional and local knowledge of bears in the region. This information largely remains unconsolidated. Through extensive searches of literature, historical documents, and interviews with researchers in the area, we hope to consolidate this information in a written and spatially oriented, digital format. Where necessary, traditional knowledge and local information will be augmented and updated through further interviews. We will try to integrate local knowledge of grizzly bears with scientific knowledge using belief system modeling.
Management Implications
There have been several grizzly bear studies in and around the region considered the Yukon North Slope. All data derived from these studies are problematic for understanding the current population size and structure. The first bear study done in the Yukon North Slope was conducted in the Barn Mountain area in 1972 to 1975 (Nagy et al. 1983). This study obtained information on the morphological characteristics of bears, denning habits, and population parameters. Unfortunately, during the 1970s, the more sophisticated mark-recapture analyses that are commonly used today were not widespread in use. Therefore, to get a population estimate, researchers used a direct aerial count of bears. However, no correction factors were applied for distance sightability, or pelage and habitat sightability. Not accounting for these biases can result in an underestimation of bear density. In addition, immigration and emigration, or residency issues were not considered. This could have led to a gross overestimation of bear density. Further to these problems, the Barn Mountain study was not considered extensive enough to derive reproductive information on a representative sample of females (Nagy 1990) and the physiographic characteristics of the Barn Mountain Range do not resemble the rest of the North Slope. Nagy (1990) also noted that the duration of the study (three years) was not long enough to capture the reproductive cycle of females. He recommended that a five- to ten-year study be used instead for obtaining this information. As a consequence of these issues, the majority of the data collected from this study were not used to establish current harvest quotas for the Yukon North Slope. Instead, population parameter estimates were borrowed from other studies throughout the ISR and neighboring Alaska.
In 1993 a study was initiated in the Richardson Mountains (Nagy 2003). This study was completed in 2001. Unfortunately, in the year this study was due to commence, a high number of male bears were shot in the area. Researchers suspect that this high mortality of adult males caused an influx of young males (Nagy 2003) into the area and could have lead to inflated population estimates, suppressed reproductive parameter estimates, and inaccurate sex ratio estimates. Further, no mark recapture analyses were done for the area. The results of this study more accurately represent the changes that occur in population structure following overharvest, and less so reflect a population from which harvest quotas should be modeled.
In 1993, a habitat mapping study was conducted in the Firth River corridor (Mackenzie and MacHutchon 1994). This study did not estimate any population parameters, but looked solely at habitat mapping along the narrow corridor surrounding the Firth River. Eight bears (five adult females and three adult males) were collared during this study, but observations of these bears were restricted to habitat use, activity budgets, food habits, and movements.
In November 2002 members of the Inuvialuit Hunter and Trappers Committees (HTCs), the WMAC boards, Yukon and Northwest Territory governments and Parks Canada met to discuss needs for managing grizzly bear (Ursus arctos) populations in the Inuvialuit Settlement Region (ISR). Members of the Aklavik HTC felt that there was a need to update population estimates for the North Slope. The Yukon North Slope Research and Monitoring Plan and the Co-management Plan for Grizzly Bears in the Inuvialuit Settlement Region, Yukon and Northwest Territories also indicated a need to update population estimates for grizzly bears, and to review harvest rates using population-specific information.
Budget