136 wolves at year's end in Yellowstone Park.

Wolf population figures are in for 2006 for Yellowstone Park. Ten breeding pairs, 136 wolves, and 13 packs were identified after intensive observations.

It is fascinating to compare this year’s figures with the past.

The wolf population in the Park peaked in 2003 with 174 wolves. At the end of 2004 the population was essentially the same, 171 wolves, but after very high wolf pup mortality in 2005, the Park wolf population dropped 30% to 118 wolves, the first real decrease in the history of the wolf recovery program in the Park.

In 2006, there was excellent pup survival. Seven-five pups were born and 60 survived until Jan. 1, 2007. The total wolf population grew by just 18 wolves to 136. About 45% of the Park’s wolf population is pups!

The reason for the slow regrowth of the wolf population is mostly out-migration.

Two wolf packs formed in the Park, but left. The Swan Lake Pack regenerated (near Swan Lake Flat), but in November they exited to the north, and their located is presently unknown. The Snake River Pack formed near the South Entrance to the Park. They were discovered rather late in the season and none of them were collared and are believed to be somewhere south of the Park.

Conflict between wolf packs resulted in the Slough Creek Pack having no pups as they were beseiged at their densite by a pack of wolves still called “the Unknowns,” but suspected by many to live north of the Park. The Unknowns did not stay in the Park.

The Agate Creek Pack was very aggressive, attacking both the Sloughs and the Hellroaring Pack, and maybe the new Oxbow Pack too, which might account for the Hellroaring Pack losing all of their pups-of-the year.

The reason long-time Agate leader 113M is lagging behind the rest of the pack is now known. In a recent battle with the Sloughs, his testicles were severely injured. The damage is obvious to observers.

Lately the Slough have been gaining reinforcements. A month ago, they had lost their alpha male. He was the only male. He was killed by prey or the Unknowns? near the north boundary of the Park. The pack was just 7 females, a situation that would not stand. Soon an ambitious gray-colored, Agate yearling jumped at the opportunity, and he seems to now be the new alpha male of the pack (no radio collar). The acceptance ritual was described by Kathie Lynch in an earlier report. Later a lone female wolf joined the pack, and on Jan. 23, Dr. Doug Smith told me a new gray-colored male walked right into the pack and seemed to be accepted.

Radio collaring of wolves has been going on, and this year they made their biggest effort ever with the remote Yellowstone Delta pack. They caught them in the Thorofare and collared 5 of the often large pack, which had gradually become collarless.

One pack member received an Argus GPS collar which emails biologists its position. The Delta Pack has spawned numerous pack that have left to the south, and perhaps not surprisingly, the pack member with the GPS collar soon left the Park and the Thorofare area. He travelled high into the snowbound Absaroka and crossed the pass at the top of Open Creek, descending into the South Fork of the Shoshone.

Dr. Smith told me today he had calculated that over the 11 years of wolf recovery 78 radio collared wolves had dispersed from the Park, and not one wolf or pack had been know to migrate into the Park and stay (lone wolves had occasionally passed through, and packs had showed up twice for a couple weeks (this includes the “Unknowns” from last May).

My conclusion is that the Park is a wolf source and the outside a wolf sink. Smith’s conclusion was that this may explain why mange has never been a problem in the Park. The Park has no manage, and wolves (potentially with mange) do not migrate into the Park.

Print Friendly