Who Made Stork Fart?

Stork has a TV show on good manners. Lately, she's pointed out the uncouth manners of several animals in the zoo. Warthog, Grizzly and Pelican have been the target of her piques. So when Stork is the victim of a whoopee cushion which makes her look like a disgusting bird on live TV, Sherlock scrutinizes the three suspects.