Actually, we heard only one, but we suspect she has more because her first litter two years ago was two cubs (Dot and Donna).

As dusk faded today, two of us stood 12 feet from her above-ground nest in a jumble of fallen balsam fir trees.  As each minute passed without a sound, our hopes for cubs faded.   She didn't even lift her head, which made us think she was too deep in hibernation to be caring for cubs.  But she was not breathing the long, deep breaths of deep hibernation.  The breaths were several per minute and were not held for a few seconds before exhaling.  That kind of breathing usually signifies that a hibernating bear is alert.  Then we heard a cub cry underneath her, and Blackheart's behavior made sense.  

She hadn't raised her head because she was breathing on her cub(s) to keep it warm in the first critical days of life--like a brooding bird is reluctant to remove itself from eggs that are about to hatch.  The cubs made us doubly happy that we had not put Blackheart out of her misery last summer after she was hit by a pickup truck.   Witnesses said that when she regained consciousness on the highway, she dragged herself slowly and painfully off into the woods.  But our examination showed that she was not paralyzed, and her vital signs were good.  We brought her food and water until she could move better. 

Having cubs was the last sign we were looking for that she has fully recovered.