Female Pileated Woodpecker (Dryocopus pileatus) and likely Yellow-rumped Warbler (Dendroica coronata). Pileateds are zealous in their pursuit of bugs in rotting trees, excavating large, rectangular holes to access insect galleries, leaving behind cavities that numerous other birds and critters use for nesting and protection from the elements. They perform a vital service for their communities in this respect.