Just to
complicate things further - a scan of the current Clements list of birds of the
world gave:
Sulphur-winged Parakeet, Yellow-crested Cockatoo  C.
sulphurea, Sulphur-crested Cockatoo, Yellow-throated Tinkerbird  P. 
subsulphureus, Sulphur-bearded Spinetail  C. sulphurifera, Sulphur-bellied
Tyrant-Manakin  N. sulphureiventer, Sulphur-bellied Tyrannulet,
Yellow-olive Flycatcher  T. sulphurescens, Sulphur-rumped Flycatcher 
M. sulphureipygius, Sulphury Flycatcher  T. sulphurea, Sulphur-bellied
Flycatcher, Great Kiskadee  P. sulphuratus, Golden-bellied Gerygone 
G. sulphurea, Sulphur-bellied Whistler  P. sulfuriventer, Sulphur-breasted
Bushshrike  T. sulfureopectus, Sulphur-billed Nuthatch  S.
oenochlamys, Sulphur-bellied Bulbul  I. palawanensis, Sulphur-bellied
Warbler, Sulphur-breasted Warbler, Brimstone Canary  S. sulphuratus,
 Yellow Bunting  E. sulphurata, Sulphur-rumped Tanager, and
Sulphur-throated Finch.
 
However,
there is also:
Keel-billed
Toucan  R. sulfuratus, Sulphur-bellied Whistler  P. sulfuriventer, and
Sulphur-breasted Bushshrike  T. sulfureopectus.  [All scientific names
and two in both lists]
 
One of those
birds is on the US list. Google gives 3640 hits for Sulphur-bellied flycatcher,
58 for Sulfur-bellied flycatcher.
 
"A rose by
...."
 
The only
thing I conclude to this is that it is time I went back to South
America.
 
With
apologies
 
Tim
Murphy