In describing Zostercps westernensis of Quoy and Gaimard in the "Catalogue of Birds in the British Museum," Dr. R. Bowdler Sharpe makes the following observations :— "An Australian specimen has been described, and it is extraordinary that a bird which seems to be widely distributed on that continent should so much have escaped notice, the only allusion to the species that I can find in Mr. Gould's work being a passage where he mentions that some specimens of Z. Coerulescens have the throat wax-yellow. It seems to be the Z. Westernensis (Q. & G.), a species re-instated in the system by Dr. Hartlaub (J. f. O. 1865) p. 20."
With a view of solving the mystery why so common a species should have been overlooked by most writers, I have given this subject my attention for the past two years, by careful observation and the collecting of a number of specimens of Zosterops found in the neighbourhood of Sydney.