Historical clue formulations

• Large flightless birds — 2026-01-25
• Cousins of cassowaries — 2023-11-09
• Relatives of emus — 2018-09-02
• Cousins of emus — 2017-04-03
• Cousins of ostriches — 2015-10-05
• Ostrich cousins — 2014-04-02
• Birds with a name from Greek myth — 2007-08-17
• Ostrich cousins — 2007-04-11
• Flightless birds — 2006-07-30
• Ostrichlike birds — 2003-02-16
• Flightless birds — 1999-03-04
• Perlman and others — 1996-03-31
• South American ostriches — 1996-01-14
• Three-toed birds — 1994-05-16