What's the difference between guacharo and oilbird?

Guacharo

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Definition:

• (n.) A nocturnal bird of South America and Trinidad (Steatornis Caripensis, or S. steatornis); -- called also oilbird.

Example Sentences:

Oilbird

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Definition:

• (n.) See Guacharo.

Example Sentences:

• (1) Oilbirds can navigate in total darkness by echolocation.