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.

Bear Activity
There were 2,514 bear sighting and sign reports recorded in YNP in 2007. These reports included 1,527 observations of grizzly bears, 673 observations of black bears, and 39 observations where the species of bear could not be determined. In addition, there were 142 observations of grizzly bear sign (tracks, feeding sites, rub trees, dens, etc.), 7 observations of black bear sign, and 126 observations of bear sign where the species of bear could not be determined. The first observed grizzly bear activity in 2007 was a track in the snow observed in the Firehole River drainage on March 5th. The first grizzly bear observation of the year was a sighting of an adult grizzly bear bedded down in the Indian Creek drainage on March 6th. The first observed sighting of a sow grizzly bear with cubs was in the east-central portion of the park on May 14th, the sow had 3 cubs-of-the-year with her. The last observed grizzly bear activity of the year was of a grizzly bear walking down the middle of the road just north of Biscuit Basin in the Old Faithful area on November 25th. The first observed black bear activity of the year was of an adult black bear walking towards a freshly killed elk carcass at Rainy Lake on March 16th. The last observed black bear activity of the year was of a black bear cub-of-the-year observed in the Old Faithful developed area on November 25th.

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.

Cub Production
At least 14 distinct females with home ranges either wholly or partially within YNP produced cubs in 2007. The 14 females produced at least 33 cubs. Average litter size in YNP was 2.4 cubs per litter. There were 2 one-cub litters, 5 two-cub litters, and 7 three-cub litters observed. Some of the females observed with cubs in the park in 2007 had home ranges entirely within the boundaries of YNP, while others likely had home ranges that overlapped the park boundary.

Bear Mortality
Due to the grizzly bears low reproductive rate and vulnerability to human-caused mortality, it is important for the conservation of bears to keep mortalities at a sustainable level. The number of grizzly bear cubs produced in YNP 2007 exceeded the number of human-caused grizzly bear mortalities that occurred in the park. In 2007, there were 2 known grizzly bear mortalities due to natural causes and 1 grizzly bear management removal in which the bear was sent to a research facility (Table 5). Additionally, there was 1 black bear mortality due to natural causes and 1 black bear mortality due to a collision with a vehicle.

Marooned Yearling Grizzly Bear Survives
In late June of 2005, two yearling grizzly bears that appeared to be marooned on Stevenson Island in Yellowstone Lake were captured and taken by boat to the mainland where they were released. The yearlings appeared to have been marooned on the island after their mother abandoned them and swam for shore. In mid-October of 2007, one of the yearlings was recaptured at Flat Mountain Arm of Yellowstone Lake during a research trapping effort, proving that at least one of the two marooned yearlings had survived.

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
The average litter size for grizzly bears in the Yellowstone Ecosystem is approximately 2 cubs per litter. Litters of one, two, and three cubs are common. It is extremely rare to see litters of four cubs in Yellowstone, although litters of 4 have occasionally been documented. In mid-August, 2007 a female with four cubs was observed in the Antelope Creek/Dunraven Pass area of Yellowstone National Park. The Parks Bear Management Office believes the female adopted two of the cubs. Throughout the summer of 2007, there was a highly habituated unmarked female grizzly bear with two cubs observed along the road in the Antelope Creek drainage. This family group was first observed in late May and was photographed by hundreds of park visitors at roadside bear-jams throughout June, July, and early August. There was also a 24-year old radio collared female grizzly bear (#125) with three cubs whose home range encompasses the Antelope Creek drainage. Grizzly bear #125 is not habituated to people and was not observed as frequently as the habituated female with two cubs. Grizzly Bear #125 was observed multiple times both from the ground and during radio telemetry flights from fixed-wing aircraft. Grizzly Bear #125 had three cubs each time she was observed in June and July. On August 12th the unmarked, habituated female was observed with four cubs instead of two cubs. From the size and color of the cubs, it appeared that the adult female had her original two cubs plus two additional cubs. The unmarked habituated female was observed with the four cubs numerous times between August 12 and September 13. During a telemetry flight on August 16, radio marked grizzly bear #125 was observed with only one cub.

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.

Safety Message
Park visitors should be aware that all bears are potentially dangerous. Park regulations require that people stay at least 100 yards from bears (unless safely in your car as a bear moves by). Bears need your concern not your food. It is against the law to feed any park wildlife, especially bears. In areas like Yellowstone National Park where there are very few human-caused bear mortalities, bears will learn that people are not a threat and will tolerate people at close distances. This behavioral response is referred to as habituation. To ensure that you do not put yourself or habituated bears at risk, please follow these guidelines when viewing or photographing roadside bears:

• Do not stop your car in the roadway to view or photograph roadside bears. Park in established turnouts and make sure your car is completely off of the paved roadway.
• Make sure you put your vehicle into park, and engage your parking brake.
• For your safety, view or photograph bears from your vehicle. If you exit your vehicle, stay near your vehicle so that you can get inside if the bear approaches. There is no guarantee of your safety if you stop your vehicle to view bears, especially if you exit your vehicle.
• Avoid being struck by a moving vehicle, do not stand in the roadway while viewing or photographing bears.
• Maintain a safe distance, at least 100 yards from bears.
• Never surround, crowd, approach or follow bears.
• Don’t block the bears line of travel.
• Do not run or make sudden movements, this may cause bears to attack.
• Watch other people in the area, are they putting you in danger?
• Do not feed bears.

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.