Abstract
This research examined morphological characters useful for age determination of male Narcissus Flycatcher Ficedula narcissina. First summer males showed shorter natural wing and tail lengths than 2nd summer or older, but there were very significant overlaps in the measurements. Tibial feather color changed with age. First summer plumage was all light brown feathers; while a small number of grayish black feathers appeared during the 2nd summer. Birds of 3rd summer or older showed a dense covering of pure black feathers. Iris color was also different with age; from grayish brown in the 1st summer, to brown in the 2nd summer, to reddish brown in the 3rd summer and afterwards. These results show that both tibial feathers and iris color are useful traits for determining the age of male Narcissus Flycatcher.
