Tropical Gnatcatcher (Polioptila plumbea) - HBW 11, p. 373

Taxonomy: Todus plumbeus J. F. Gmelin, 1788, Suriname.
Possibly forms a superspecies with P. lactea, and some earlier suggestions that the two may be conspecific. Because interspecific morphological variation within this genus is often very subtle, it is thought likely that this taxon consists in fact of several species; study of genetic and vocal characters of various populations clearly warranted. Races form at least three distinct groups, i.e. the “bilineata group” (also including superciliaris, brodkorbi and cinericia), the “nominate group” (with anteocularis, daguae, innotata, parvirostris, plumbiceps and atricapilla) and maior; last-mentioned is almost certainly a separate species. Relative distributions of nominate race and innotata in E Brazil (in region roughly from C Pará E to WC Maranhão) unclear; more study needed. Records from E Ecuador and adjacent N Peru (NW Loreto) tentatively considered to refer to race parvirostris; locality of a specimen labelled as this race from W Brazil (C Amazonas) is roughly equidistant from localities of specimens representing innotata, nominate and parvirostris. Original description of cinericia based on comparison with bilineata, rather than with adjacent mainland superciliaris; further study needed to clarify whether cinericia should be synonymized with latter. Name of race maior has sometimes been listed as “andina”; latter name may indeed refer to this taxon, but “maior” still retains priority. Twelve subspecies recognized.