This information comes from Kevin Sanders and Deb Guernsey with my interpretations added. Please note that Kevin has new first hand observations of wolves from the Lamar Valley. Check his page out at Bearman's

There are four new pups in the Park, but they were born by no. 37F inside the Nez Perce enclosure. The father would be no. 29M who had been penned with no. 37 ever since last summer, but escaped the pen this March. Soon after his escape most of the Sawtooth pups were released in the hope that they would join him, which they now seem to have done. I should add that they are not pups anymore, but yearlings, nearly fully grown.

When captured in British Columbia, it was thought that no. 37 and 29 were siblings, the offspring of no. 28M and 27F. I understand Mike Phillips is going to do some DNA testing to verify the lineage of 37 and 29. Siblings usually do not mate. Nos. 27F, 37F, 48M, 66M, and 70M were being retained in the pen for release in late May or early June in the southern part of the Park. These plans are now obviously on hold.

Most of the Sawtooth pups plus no. 29M and 33F, are currently frequenting the area along the western boundary of the Park just north of West Yellowstone (see the photo of the Park boundary at Duck Creek below). They move in and out of the Park between Duck Creek and go westward to Rainbow Point on Hebgen Lake Reservoir (this is a fairly large reservoir on the Madison River). Some might remember Rainbow Point as the site of the gruesome killing and consumption of a young man by grizzly bear about 14 years ago.

Here is the photo of the Park boundary at Duck Creek (looking toward the south). This gives some idea of how indefinite the Park boundary is in the area. Hebgen Lake is not in sight (it's a couple miles to the right of the photo area).

On the Park boundary at Duck Creek (right corner).
Yellowstone Park is to the left. © Ralph Maughan

Duck Creek is an area of incredible wildlife habitat inside the Park. It's good outside the Park too, but the Duck Creek area outside the Park is a busy place, with lots of auto and truck traffic on U.S. 191 and quite a few summer homes in the area. It is not a heavily-developed area, however, and grizzlies wander the area (and now wolves). This is also the site where the State of Montana conducted much of its bison killing last winter. U.S. 191, a few miles to the north of Duck Creek, was the place where wolf 32F was runover by a semi-truck in the middle of night last June. She had been the alpha female of the Chief Joseph Pack.

I should add that there are plans afoot to put in a golf course and several hundred condos at Duck Creek right up against this incredible wildlife habitat -- another sad story of how developers are ripping apart the Greater Yellowstone ecosystem.

Additional item
I reported this earlier, but since I am replacing the old article, I want to repeat it:

The Lone Star Pair, deep in the Thorofare Country, appear to be denned and so has the Crystal Creek Pair. Earlier I had speculated that no. 5F, the Crystal Creek female would probably never have pups, although she was observed mating in 1995 (in the Crystal Creek pen) and appeared to den in 1996. Some have speculated that she did have pups in 1996, but they were killed by the Druid Peak as was her mate No. 4M. This is only speculation about the pups.