ant birdn1. (Animals) any of various dull-coloured South American passerine birds of the family Formicariidae, such as Hylophylax naevioides (spotted ant bird), that typically feed on ants. Also called: bush shrike or ant thrush Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014