Homobatrachotoxin in the Genus Pitohui: Chemical Defense in Birds?

• Dumbacher, John P.
;
• Beehler, Bruce M.
;
• Spande, Thomas F.
;
• Garraffo, H. Martin
;
• Daly, John W.

Abstract

Three passerine species in the genus Pitohui, endemic to the New Guinea subregion, contain the steroidal alkaloid homobatrachotoxin, apparently as a chemical defense. Toxin concentrations varied among species but were always highest in the skin and feathers. Homobatrachotoxin is a member of a class of compounds collectively called batrachotoxins that were previously considered to be restricted to neotropical poison-dart frogs of the genus Phyllobates. The occurrence of homobatrachotoxin in pitohuis suggests that birds and frogs independently evolved this class of alkaloids.