The most common and most likely answer to this crossword clue is the 7 letter word QUETZAL
I've seen this crossword clue in Independent
Q
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The straight part
We know that "gaudy bird" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gaudy bird = quetzal.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does QUETZAL mean?
QUETZAL noun- Any trogon of the genus Pharomacrus, especially the resplendent quetzal, Pharomacrus mocinno, which has very long tail feathers and is found in Guatemala and Costa Rica.
- A monetary unit used in Guatemala, equal to 100 centavos.