Why not? "We really can't get a tight fit with our beaks in the way. We could possibly protect our nares, but that's it." Ah, right … "And even then, it could probably still affect us if we didn't have something to cover our eyes. So at best, we'd be half-blind, couldn't speak, and the kidnapper can still just wait for the shirts to dry out before gassing us again, quackidee!"