
Photo: Vitty and Seaborne · Public domain
Cyornis ruckii
Habitat
Primary lowland forest
Range
Endemic to a small area of north-east Sumatra
Rück's blue flycatcher is known from only four specimens and is endemic to a small area in north-east Sumatra, inhabiting primary lowland forest. All specimens share a black bill, brown iris and black feet, though two show some physical discrepancy with the others (Wikipedia, general species account).