Bear Management Update
Grizzly Bears in the Yellowstone Ecosystem Removed From Threatened Species Status
On April 30, 2007, after more than 30 years of receiving special protection, the U.S. Fish and Wildlife Service (USFWS) removed grizzly bears in the Greater Yellowstone Area from threatened species status. The grizzly bear was listed as a threatened species under the Endangered Species Act (ESA) in 1975 because of unsustainable levels of human-caused mortality, loss of habitat, and significant habitat alteration. Since then, with state and federal public land and wildlife managers as well as non-government organizations working together for the conservation of grizzly bears and their habitat, the species has made a remarkable recovery, probably one of the greatest conservation successes in the history of the United States.
In the GYA, grizzly bear cub production and survival have been high in recent decades and human-caused mortality has been kept at sustainable levels, allowing the population to increase from an estimated 136 bears in 1975 to approximately 600 bears in 2007. In addition, grizzly bears have expanded the range they occupy by over 48% in the last two decades.
Although grizzly bear recovery is a great success story, removal from threatened species status does not mean that grizzly bear monitoring and protection of bear habitat will no longer be a priority. The grizzly bear population will likely always need to be closely monitored and carefully managed, including efforts to control human-caused mortality. Prior to delisting, the state and federal managers responsible for managing the grizzly bear population and habitat in the GYA completed a Conservation Strategy for the Grizzly Bear in the Greater Yellowstone Area. The document will guide grizzly bear management by state and federal agencies that manage grizzly bears or their habitat in the Greater Yellowstone Area. The plan describes the agencies’ coordinated efforts to manage the GYA grizzly bear population and its habitat to ensure its continued conservation. It specifies the population, habitat, information and education, and nuisance bear standards necessary to maintain a recovered grizzly population for at least the next century.
In areas like YNP where bears and people come into frequent, benign contact and there are few human-caused bear mortalities, bears will habituate to people. Habituation has been defined as the waning of an animal’s flight response following repeated exposure to inconsequential stimulus. Habituation also allows bears to access and utilize habitat in areas with high levels of human activity. In YNP, human-habituated behavior by bears is most often observed along park road corridors. When habituated bears are present along roadside corridors during daylight hours, hundreds of visitors may stop along the road to view and photograph the bears, causing traffic congestion; these incidents are referred to as bear-jams. In 2007, 822 bear-jams were reported. Grizzly bears were involved in 380 of the bear-jams, and black bears in 434. The species of bear was not identified in 8 bear-jams.
Marooned Yearling Grizzly Bear Survives
In early June of 2005, the Lake Queen II tour boat observed an adult female and two yearlings on Stevenson Island. The family group had probably walked over the ice to the island while the Lake was still frozen. Bear Management Office staff investigated the shore of the island and found numerous tracks and scats of an adult grizzly bear and at least two yearlings. The age and quantity of the scats and tracks indicated that the bear family group had likely been on the island prior to the ice breaking up on Yellowstone Lake on May 23rd. When the ice broke up the bears had likely become stranded. Bear Management staff placed a bait station and tracking pit on the northwest end of the island to determine if the bears were still present. When the bait station/tracking pit was revisited, tracks of two yearlings but no adults were found, suggesting that the adult female may have swum for the mainland abandoning the two yearlings. Due to their small size, the two yearlings may have been afraid to swim the 1.4 miles to the nearest mainland shore at Gull Point or Sand Point.
Although plenty of succulent vegetation existed for the bears to graze, the types and quantity of late summer and fall bear foods were scarce on the small 105 acre island; if the bears remained on the island they would likely starve to death. In 1984, an adult female grizzly bear and three cubs-of-the-year were found starving to death on Frank Island. One of the cubs died of malnutrition; the adult female and remaining two cubs were captured by Bear Management staff and relocated to the mainland. In 2001, a yearling grizzly bear was found stranded on Dot Island. Evidence indicated that the yearling’s mother had been present on the island but had swum back to the mainland leaving the yearling stranded. The yearling was captured and transported to the mainland to give it a better chance of survival. Due to the grizzly bear’s status as a Threatened Species (grizzly bears were not delisted until 2007) and the likelihood that the pair of yearlings would starve to death if left on Stevenson Island (based on the Frank Island incident), the decision was made not to “let nature take its course” and instead to capture the yearlings and relocate them to the mainland where their chances of survival would be higher.
To make certain the mother bear was not on the island, several bait stations with remote camera’s were set up on the island. The camera’s captured photo’s of two yearlings but no adult bear, at the bait stations. Three traps were set, but both yearlings were caught in one trap. The yearlings were given meat and water and left in the trap overnight surrounded by remote camera’s aimed at the trap in another attempt to determine if the mother bear was still present on the island. With the cubs periodically bawling from inside the trap, the mother was certain to come to their aid and be caught on camera if she was still on the island. When the mother did not show up at the trap, the yearlings were immobilized and fitted with ear-tag transmitters, a pit tag, and a tattoo. Both yearlings were females and weighed 71 and 76 pounds, respectively. The yearlings were slightly underweight for their age, but healthy. We estimated their chances of survival at 50% and as high as 80% if they rejoined their mother on the mainland. In a final effort to determine if the adult female was still on the island, the entire island was hiked and searched by Bear Management Office staff. Numerous scats, tracks, and day-beds were found, but the adult female bear was not on the island. The yearlings were allowed to recover from the immobilization drug, then transported by landing craft to Charcoal Bay of the South Arm of Yellowstone Lake where they were released. The bears were last observed grazing together just above the beach at Charcoal Bay. They were monitored by telemetry for the rest of the summer and based on their movements were thought to have survived the summer and fall. By late fall both bears had lost their transmitters and could no longer be monitored.
In mid-October of 2007, the Interagency Grizzly Bear Study Team captured one of the yearlings in a research trap aling Flat Mountain Arm of Yellowstone Lake. The now three-year-old bear was identified from the lip tattoo applied when the bear was rescued from exile on Stevenson Island. She was slightly small in body size for a three year old bear and weighed only 176 pounds, but she had a layer of fat and was generally healthy. We do not know if her sibling has survived. Maybe someday her sibling will be recaptured as well. Park staff has the satisfaction of knowing that their efforts to rescue the bear had paid off and at least one of the marooned yearlings is now known to have survived.
Female With Four Cubs Observed Near Dunraven Pass
Although circumstantial, the evidence suggests that the habituated female likely adopted two of radio collared Grizzly Bear #125’s cubs. The home ranges of both adult females over-lapped. The unmarked habituated female with two cubs gained two additional cubs about the same time that radio marked Grizzly Bear #125 lost two of her cubs. To determine if the adopted cubs belonged to Grizzly Bear #125, the Bear Management Office set up a hair snare with a remote camera in the area commonly frequented by the unmarked habituated female with the four cubs and successfully collected hair samples from the family group. The IGBST already has hair samples on file from radio collared female Grizzly Bear #125. DNA analysis of these hair samples will be used to determine if the adopted cubs came from Grizzly Bear #125, and if the unmarked habituated female is one of Grizzly Bear #125’s offspring from a previous litter. Female offspring commonly establish home ranges within and adjacent to their mothers home range.
The details of the circumstances that led to the adoption may never be known. Possibly grizzly bear #125 and the habituated female crossed paths while foraging, maybe the five cubs played or otherwise interacted, and, upon leaving two of #125’s cubs followed the wrong mother. Possibly Bear #125 and her three cubs had an encounter with a pack of wolves or an adult male grizzly bear (both known to kill cubs) and the family group scattered during the interaction and two of the cubs became separated and later were adopted by the unmarked habituated female. Regardless, the female grizzly bear with four cubs was viewed, photographed, and enjoyed by thousands of awestruck park visitors as the bears foraged, played, and nursed on the slopes of Mount Washburn during the late summer and early fall.
For visitors venturing into the park backcountry for a day or overnight hike, safety can be enhanced by hiking and camping in groups of three or more people, restricting your hiking only to the late morning and early afternoon hours, staying on designated hiking trails, carrying EPA approved Bear Pepper Spray (and knowing how to use it), and making noise and being alert to avoid surprise encounters with bears. Most bear-inflicted human injuries in Yellowstone National Park involve surprise encounters between hikers and female grizzly bears with cubs. If a bear is encountered and surprised at close range, biologists recommend backing away slowly, then leaving the area. If the bear charges, stop, stand your ground, and deploy your bear pepper spray if you have it. Bear spray has been highly effective at stopping aggressive behavior by bears. If a surprised bear charges at you and makes contact, “play dead”. Lay on the ground on your stomach, face down with your hands behind your neck and your elbows protecting the sides of your face. Leave your pack on as this will help protect your back. Once the bear has determined that you are no longer a threat, it will usually gather up its cubs and leave the area. Make sure that the bear is gone before you get up to leave.
Did You Know?
Yellowstone contains approximately one-half of the world’s hydrothermal features. There are over 10,000 hydrothermal features, including over 300 geysers, in the park.