Dear Mike,

Thanks for your reply regarding use of Humphrey-Parkes (H-P)
terminology. Let me begin by saying that as an expert on this topic, I am
sad to say that there are few ornithologists who fully understand and
correctly use the H-P system. Indeed, I have misused it before. This is
not because the H-P system is too complex or cumbesome to understand
or use, but rather, I think, results from two causes: (1) few people read
Humphrey and Parkes 1959 (and 1963) papers, and (2) they rely on
subsequent synopses of H-P in textbooks or elsewhere (such as the
article you mentioned in Birding) that misrepresent the H-P system.
Countless books present tables that purport to show how some other
nomenclatural system corresponds to H-P terminology. As I said in my
last e-mail, this is rubbish. If such a simple one-to-one correspondence
existed, then the H-P system would be nothing more than a purely
semantic renaming of names.

Regarding the term EVOLUTIONARILY HOMOLOGOUS molts (and their
resulting plumages), it refers to the evolutionary origins of molts and can
be applied to sequences of molts both within species (between sexes
and among age classes) and among different species. For example, in a
genus of birds, one species must be the most ancestral species and the
others drevided from it at different times. Because of different selection
pressures on these species, the molt sequences of the various species
derived from the ancestral species may have changed; entire molts may
have been lost or added; timing of molts may have changed between
species or even within species (e.g. between sexes); extent of feather
replacement may have changed; and plumage color changes may have
cahnged as well. Such changes often make it difficult to determine how
the sequence of molts in one species correlate with (i.e. are
"evolutionarily homologous to) the sequences of molts in other species
(or even between age classes within species in some cases). The goal
of the H-P system is to do this. Hope this makes sense.

I also stated that trying to find rules other than those based on
evolutionary homology for applying H-P are doomed to failure. You said
you're "not sure this is quite so....that its basic concept seems quite
straightforward....[that] past the juvenile feather-suite, the bird is in Basic
or Alternate [plumage] or molt between them." Unfortunately, this is not
so. Although relatively uncommon, many species have more than two
molts and plumages per year (molt cycle), the extra molts being
presupplemental molts, and the resulting plumages supplemental
plumages. Well known examples include ptarmigans, most cardinalids,
some wood-warblers (e.g. Yellow-breasted Chat), etc. In addition, and
more common, are enormous differences in timing of molts between
sexes of many species that lead people to misidentify the molt/plumage
of males or females. This is especially true in many ducks and also in
ptarmigans (as two of many examples). The same difficulties may be
encountered between age classes within species because of
differences in the timing and extent of molt (and resulting color changes)
between age classes. So, I'm sorry, but I disagree with you on this
point.

You say you have achieved success with the H-P system where other
systems failed you. It is not clear to me how the H-P system helped you
whereas the others failed you. I'd be happy to hear your explanation.

Regarding your last point about using the H-P system "successfully and
correctly ... without reading the original paper," I'm not sure what you
mean by "successfully and correctly," and similarly, do not know what
unsuccessful or incorrectly would mean to you. I can only reiterate
what I said above. The H-P system has been and continues to be
misunderstood and misrepresented by mant ornithologists, ornithology
texts, and other major ornithology monographs. There is NO substitute
for reading the original paper. If you want an illustration of some of the
complexities and difficulties of applying the H-P system correctly, read
the following paper:

Thompson, C. W., and M. Leu. 1994. Determining homology of molts and
plumages to address evolutionary questions: a rejoinder regarding
emberizid finches. Condor 96:769-782.

Hope this helps.

Best regards,

Chris