Modifiers matching duck:

• small,
• tenacious,
• breeding,
• daffy,
• jealous,
• optimistic,
• short-tempered,
• determined,
• slobbery,
• brash,
• insecure,
• larger,
• here,
• domestic,
• rare,
• indigenous,
• bullying,
• lisping,
• wild,
• smaller,
• common,
• boastful,
• unusual,
• aggressive,
• paranoid,
• marine,
• zany,
• native,
• pushy,
• large,

Simple categories matching daffy:

• duck,
• philanthropist,
• person,
• billionaire,
• recluse,