The study of Slikas et al. on mitochondrial sequence data included samples of Zosterops conspicillatus, Z. semperi, Z. hypolais, Rukia oleaginea and Cleptornis marchei.  They found genetic divergence figures between them in the range of 5.7 to 7.3%. 

Also a difference of 6.5% was found for the Rota Island population of "conspicillatus" compared to populations from Guam, Tinian and Saipan, which is the basis of this split.  The Rota population has declined dramatically in recent years.

Rota White-eye     Zosterops rotensis
Takatsukasa & Yamashina   1931
w Pacific Ocean: Rota Island, s Mariana Islands
split from: Zosterops conspicillatus
insert after: Zosterops conspicillatus
Beth Slikas, Isaac B. Jones, Scott R. Derrickson & Robert C. Fleischer,
Phylogenetic relationships of Micronesian white-eyes based on mitochondrial sequence data
The Auk 117, 2 (2000): 355-265
 

Sangihe White-eye     Zosterops nehrkorni
Blasius  1886
ne Indonesia: Sangihe Island, off ne Sulawesi
split from: Zosterops atrifrons
insert after: Zosterops atrifrons
Pamela C. Rasmussen, J.C. Wardill, Frank R. Lambert & J. Riley,
On the specific status of the Sangihe White-eye Zosterops nehrkorni, and the taxonomy of the Black-crowned White-eye Z. atrifrons complex
Forktail 16 (2000): 69-80
 

Seram White-eye     Zosterops stalkeri
Ogilvie-Grant  1910
e Indonesia: Seram Island
split from: Zosterops atrifrons
insert after: Zosterops nehrkorni
Pamela C. Rasmussen, J.C. Wardill, Frank R. Lambert & J. Riley,
On the specific status of the Sangihe White-eye Zosterops nehrkorni, and the taxonomy of the Black-crowned White-eye Z. atrifrons complex
Forktail 16 (2000): 69-80