Small owls, such as western screech and northern saw whet owls, weigh between 3 and 7 ounces, or about the same weight as a small cell phone or a deck of cards.
They prefer dark, narrow spaces for nesting and roosting, which is why they are called cavity birds. Their habitat preferences make them prone to using man-made features, such as open pipes, that mimic their natural nesting and roosting cavities. But on some public lands, that natural act of finding habitat in ventilation pipes has led to their death.