"Legendary Birds" is the term when naming Articuno, Zapdos, and Moltres. No other Pokemon can claim this title. These Pokemon first appeared in Pokemon Red, Blue, Green, and Yellow versions, and have been in many other games since then including Pokemon FireRed, LeafGreen, Diamond, Pearl, Platinum, HeartGold, and SoulSilver.
Related ThreadsLegendary Bird Guide - last post by @ Dec 3, 2013
Legendary Bird Help ( For New People Or People That Need Help) - last post by @ Sep 24, 2005
Legendary Bird Shrines - last post by @ Jun 17, 2004
What is the deal with not being able to catch the legendary birds in gold - last post by @ Oct 20, 2003
That Legendary Bird Statue - last post by @ Aug 10, 2003