Oriolus cinereogenys Bourns and Worcester,
Minnesota Acad. Nat. Sci. Occ. Papers (1894), 1, 16;
Proc. U. S. Nat. Mus. (1898), 20, 558, no. 304 (Tawi Tawi and
Bongao).
Bongao (Everett); Tawi Tawi (Bourns & Worcester, Everett).
"In uniting the Tawi Tawi birds with O. steerii [basilanicus] from
Basilan and Mindanao, Dr. Sharpe has evidently overlooked the fact that
the Tawi Tawi birds invariably have the cheeks and ear-coverts clear
ashy gray, while in birds from Basilan and Mindanao they are just as
invariably olive-green. As we find no exception to this rule among our
fourteen specimens from Basilan and twenty from Tawi Tawi we have no
hesitation in separating the birds from the latter locality. It may
be added that the rump of the Tawi Tawi birds is rather brighter,
and the throat decidedly lighter than in Basilan birds. Not one
of our Tawi Tawi birds shows the uniform gray throat of O. steerii
[basilanicus]. Both species show great variability in the color of
under tail-coverts. In some specimens they are pure yellow and in
others heavily streaked with black. Fifteen males from Tawi Tawi
measure as follows: Length, 203; culmen, 24.3; wing, 116.5; tail,
81; tarsus, 21." (Bourns and Worcester.)
"Four females average: Length, 200; wing, 111; tail, 76; culmen,
23.3; tarsus, 21; middle toe with claw, 21.8. Eyes usually reddish
brown, but in two cases gray; legs and feet dark drab; bill reddish
brown usually, in two cases black. Very common near Tataan, in Tawi
Tawi." (Bourns and Worcester MS.)