Modifiers matching duck:

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

Simple categories matching here:

• process,
• activity,
• duck,