Matt's expression in the 3rd panel here.. He finally gave up on trying to chase after Trixie's affection and he looks absolutely broken.
Orville could really use a hug. The Rat explains to him that His birth parents are dead, he was born to regular squirrels, grew up with an adoptive family of flying squirrels and thought himself to be a flying squirrel His heartbreaking expression here is enough to cement his Woobie status. This strip is even worse, implying that Orville may have cried himself to sleep after hearing what The Rat told him.