Facing extinction, Elon kills last of native birds (4)

I believe the answer is:

emus

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'birds' is the definition.
(emu is a kind of bird)

I cannot understand how the rest of the clue works.

(Other definitions for emus that I've seen before include "laboratory units" , "Aussie birds" , "Largest native Australian birds" , "Running birds" , "Muse about flightless Australian birds" .)

I've seen this clue in the Sydney Morning Herald.

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