Appearance
Despite its name, only the nominate subspecies has an entirely black bill, while both "A. n. occidentalis" and "A. n. spilorhyncha" have bills that are coloured chestnut and black.
Naming
Three subspecies are recognized:⤷ "A. n. occidentalis" - Chapman, 1915: Found in western Colombia
⤷ "A. n. spilorhynchus" - Gould, 1858: Originally described as a separate species. Found in southern Colombia, north-eastern Ecuador and northern Peru
⤷ "A. n. nigrirostris" - : Found in eastern Colombia, western Venezuela and eastern Ecuador
References:
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