Shirley Duck is Flick Duck's mother. As his sole guardian, she oftentimes has a hard time keeping Flick's rambunctious personality in line. As with most other adults, Flick tends to try to maintain an air of innocent sweetness when around his mom. Having raised him, however, she knows him better than most and can be firm with him when necessary.
Shirley has blonde hair unlike her son. She also wears a turquoise apron and flip flops.
The reason why Shirley Duck is a single parent is never stated on the series, though the rough edges in Flick's personality may owe somewhat to the lack of any male role model figure in his life, other than Mallard Man. Flick has never mentioned his dad. Meaning Shirley's husband could be deceased, in the military, or divorced. Flick might be adopted. Or maybe the reason Shirley's husband isn't seen or even mentioned is so Flick could have a rude personlity due to no male role model.
Shirley Duck dotes on her son and he refers to her as "mommy." In "Where Oh Where is Flick?" she was beside herself when Flick wandered off without telling her where he was going. She designed Flick's Mallard Man Halloween costume in "A Hoohaw Halloween."
She is sort of a pushover with Flick, like in the episode Picture Perfect when she couldn't find Flick, she told Opal "I'm going to be very firm." And then told Flick "If you come home I'll give you a cookie." That doesn't sound very firm at all. And in The Duck Who Cried Wolf, she told Flick "No cherry pie at all this week." And Flick said, "What about Boston Cream?" Shirley replied with "Well, Boston Cream, okay. But no cherry."