How many letters does the top answer for “large and rare arctic falcon having white and dark color phases” have?

The most common answer is gerfalcon (9 letters).

Crossword clue: large and rare arctic falcon having white and dark color phases

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

gerfalcon 9 letters wn-def

large and rare Arctic falcon having white and dark color phases

gyrfalcon 9 letters wn-def

large and rare Arctic falcon having white and dark color phases