Has foul play befallen the Yellowstone Delta Pack?

Although I mentioned this several months ago, the Yellowstone Delta Pack, has not been located since February. We thought they would eventually turn up.

This generally large pack was the most remote of all the packs in Yellowstone Park, inhabiting the area from Heart Lake, and, especially up the headwaters of the Yellowstone River in the Park and south of the Park in the Bridger-Teton National Forest's Teton Wilderness. Sometimes the pack ranged further afield toward the Park's South Entrance and into other parts of the Teton Wilderness and adjacent Washakie Wilderness.

It was a wolf pack with a habit of chewing off radio collars, but last winter 3 new collars were deployed, and 2 old collars remained. One of the collars was "armored" to prevent chewing. Chewed collars continue to give signals -- signals in mortality mode. When a group of wolves with collars simply disappears from tracking, in the past it has always meant they moved a long distance, well out of range of the tracking flights, but these wanderers have always been found. Nevertheless, since February these wolves, save for one yearling female, who seems to be alone back in the Park, have not been tracked.

The Delta pack would seem to be in a very safe location in the winter. Snowmobiles are illegal in Yellowstone Park backcountry and in both the Teton and Washakie Wilderness. The pack resided in the place furthest from a road in the lower 48 states. It would take a huge illegal operation to go in during the winter, kill the wolves, and dispose of the radio collars and the carcasses.

The wolves were generally disliked by the hunting outfitters in the Teton Wilderness. This major big wilderness is one of the prime elk hunter outfitting spots on Wyoming. I have spent hundreds of days in it over 30 years and wrote two hiking guides to it. Gary Ferguson discusses the outfitter problem extensively in his book "Hawks Rest."

The Delta Pack had two den sites. One was deep inside Yellowstone Park, but the other near the boundary. In the past several people told me some outfitters had made a point to ride all over the den area at the boundary den, although this did not seem to harm the pack or even necessarily cause them to chose another den site. In summary then, the danger to the Delta pack would seem to be in the summer and especially the fall, but not the deep winter.

Nevertheless, both the Park's tracking flights and the USFWS tracking flights for Wyoming have not found a trace, except for the apparently lone female still in the Park. If all the collars failed and the pack was still there, it seems very unlikely they would not be spotted from the air even if they are not with the lone female.

Is it possible the pack ventured out of the wilderness and was ambushed? Maybe they are at a very distant and unusual location. However, this large pack, including the huge alpha male, 487M, would seem to make their presence known. The old Thorofare Pack, whose alpha male was killed by the Delta pack's forbearers (the Soda Butte Pack) was eliminated not just by the male's death, but by the death of the alpha female a short time later in an avalanche. Could an avalanche fallen on the pack? Of course, the radio collars might have survived an avalanche.