Historical clue formulations

• Small duck — 2025-03-10
• Bird of the Baltic — 2022-10-30
• Duck variety — 2017-11-17
• Eurasian duck — 2017-05-02
• Eurasian duck — 2017-02-20
• Duck that nests in tree hollows — 2014-09-28
• Cousin of a goldeneye — 2014-07-26
• Northern duck — 2013-05-09
• Goldeneye relative — 2012-05-04
• Eurasian duck — 2011-09-13
• Old World duck — 2009-10-24
• Old World duck — 2007-06-09
• Eurasian duck — 2007-05-21
• Old World duck — 2006-06-07
• Merganser relative — 2006-05-06
• Old World duck — 2004-02-13
• Eurasian diving duck — 2003-10-24
• Duck with a large white crest — 2003-08-14
• Smallest of the mergansers — 2001-07-15
• Small merganser — 1998-05-31
• Eurasian duck — 1998-05-18
• Merganser — 1998-01-01
• Fish-eating duck — 1997-05-08
• Saw-billed duck — 1996-12-29
• Diving duck — 1996-12-13
• Eurasian duck — 1996-07-28
• Diving duck — 1995-11-24