win ho e , ▁ 1 8 6 3 ) ▁– ▁Taiwan ▁ ▁The ▁S unda ▁ow let ▁( G la uc id ium ▁s yl v atic um ) ▁was ▁formerly ▁treated ▁as ▁a ▁sub species ▁of ▁the ▁col la red ▁ow let . ▁It ▁was ▁promoted ▁to ▁species ▁status ▁based ▁on ▁the ▁results ▁of ▁a ▁vocal isation ▁study ▁published ▁in ▁ 2 0 1 9 . ▁ ▁Description ▁ ▁The ▁col la red ▁ow let , ▁being ▁Asia ' s ▁smallest ▁ow l ▁species , ▁measures ▁between ▁ 1 5 ▁and ▁ 1 7   cm . ▁Fem ales ▁are ▁generally ▁larger ▁than ▁the ▁males , ▁we igh ing ▁approximately ▁ 6 3 ▁gr ams , ▁whereas ▁males ▁we igh ▁in ▁at ▁ 5 2 ▁gr ams . ▁ ▁This ▁bird ▁has ▁a ▁grey - b rown ▁colour ▁( dep ending ▁on ▁age - m orph ) ▁and ▁has ▁a ▁bar red ▁back ▁and ▁fl anks , ▁while ▁the ▁head ▁is ▁more ▁sp otted ▁than ▁bar red . ▁They ▁have ▁prominent ▁white ▁e y eb rows , ▁v ibr ant ▁le mon - yellow - col oured ▁eyes ▁and ▁a ▁white ▁thro at ▁patch . ▁The ▁ch in , ▁center ▁of ▁the ▁breast ▁and ▁bel ly ▁are ▁mostly ▁white . ▁The ▁pale ▁col lar ▁and ▁the ▁two ▁black ▁sp ots ▁on ▁each ▁side ▁of ▁the ▁na pe ▁im itate ▁eye ▁sp ots ▁and ▁make ▁it ▁seem ▁like ▁the ▁ow l ▁is ▁st aring ▁at ▁you ▁from ▁behind . ▁This ▁is ▁known