Tracking Cassie By Michael Allen, Black Bear Researcher A dark shape moved through the fog and across the road in front of me. I peered through the lightly falling snow to make out an adult-size bear. Two raccoon-size shapes darted behind it. I raised my binoculars to identify Cassie and her cubs, residents of Whistler Mountain, entering the timber about 30 metres downhill. The family had crossed over my previous tracks, going uphill along the road. I stopped to measure the width of their fore pads. Cassie's were 10 cm and one of the cubs’ were 8 cm. I flagged the site where they had entered the timber — it was getting dark and I would return the next day to track their movements. It was Oct. 9 at 6 p.m. This early snow at upper elevations was perfect for tracking pre-denning movements of bears. Mothers with cubs or pregnant bears usually enter dens first during mid-late October, depending on the availability of late fall berries and the onset of winter weather. I returned the next morning to locate the bear family's tracks crossing over mine higher along the ski trail. This is ultimately the best way to track a bear — about a day behind its initial activity. Often tracking a bear too close will bias their natural behaviour, thereby altering the bear's intentional movements. I have tracked black bears on 81 occasions through the snow in the last five years in Whistler. It is perhaps the most intriguing part of the research because if conducted properly, I can learn exactly what bear activities take place in which habitats. Tracking bears is extremely physical, with periods of risk and danger. Hiking through forests, shrub-dominated cutblocks and along riparian areas with new snowfalls is treacherous. Also, if bears detect they are being followed they often wait for their pursuer to catch up, giving them or me a little surprise. I began following the family's trail through about 15 cm of snow. When tracking families I always try to stay on the mother’s trail — the cubs can disorient the trail by taking off and exploring, creating a maze of bear tracks. So what I end up looking at is a trail of large tracks with little ones criss-crossing over the mother's trail. Periodically, mom will stop, rest and usually nurse. I can detect this in the snow with a bum depression and many tracks in one area. The family ascended through a closed forest and emerged to criss-cross a ski trail. They often explored creeks, berry shrubs, and rotten logs for possible food sources. Cassie then took her cubs back into the forest and up into fingers of open meadows. Around 1,600 metres the trail began to ascend through small islands of mountain hemlock, balsam fir, and old growth whitebark pine. Suddenly, I noticed fresher tracks overlapping the trail downhill — these recent tracks were a brownish-grey colour, which meant the bears had been tearing at bark and walking in sawdust. Immediately I looked around for a large enough tree to accommodate a bear den. About 10 metres up-slope from the bear trail I located an old growth whitebark pine standing in a patch of white-flowered rhododendron. I listened for 15 minutes then slowly followed the trail. If the bears were inside I did not want to spook them, causing den abandonment. I assumed they were not because I had been close to begin with and she would have detected my presence already. Three steps up-slope and I could see the entrance into the tree den. I could also see the trail continue on. The family was since gone but had possibly spent last night inside of the tree. The elevation of the tree den was 1,680 metres. Mothers with cubs and pregnant bears often den in tree cavities which provide security and dryness. I was now, for the first time in five years, tracking a mother with new-born cubs above treeline. The family ascended above the Highway 86 access trail and into the boulder field of the West Bowl. By now I was following the family's tracks through 40-50 cm of snow. The tracks led straight up through an avalanche path with stunted timber. Cassie reached a large boulder in a timbered island and another existing bear den was inspected. This den was apparently an excavated chamber partially under a boulder. This was a deep and dry den. The trail pushed on again until reaching the vertical rock outcrops of the West Bowl. The family turned course and began traversing an avalanche timbered-shrubfield. Twice Cassie had attempted digging at the base of old growth whitebark pine trees while hitting a rocky substrate both times. Cassie eventually descended with her cubs below Highway 86 and back into dense forested cover. Cassie and her cub tracks were lost below snowline. Cassie's excursion to the West Bowl shed interesting data on the pre-denning movements of bear families. It identified her potential denning range and den types she might look for or excavate. Bear activity remains high in the valley while bears feed on the last berries and accessible garbage. Black bear research and education in the Whistler area is currently sponsored in part by the Jennifer Jones Whistler Bear Foundation and Whistler/Blackcomb. Questions regarding bear behaviour and activity may be directed to me at 894-1964.