On initial view from a distance, the tan colored portions in the photo here appeared to be old leaves or other detritus. But if you examine the photo at full-resolution (click it twice), you can see that those areas are actually dense clusters of mistletoe fruits. We'd seen some Cedar Waxwings visiting clumps of mistletoe earlier in the day, and they were almost certainly after the mistletoe "berries".

The Jepson eFlora treatment of P. leucarpum ssp. tomentosum is here.