Morphological variation in the Black Falcon Falco subniger

Abstract

We describe and discuss a field observation of a strongly speckle-breasted and barred Black Falcon Falco subniger that also, unusually, had yellow feet and cere and pale-yellow orbital rings. We also found several museum specimens with ‘variegated’ plumage and yellow bare parts. We speculate that yellow bare parts in this species might occur only in some individuals, perhaps mostly males, of the most variegated (pale-marked) plumage types, and that these correlated features may be age-related characters that deserve further investigation. We also discuss the implications for field identification.