418 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 124. No. 2. June 2012 
into their lour molt strategies. Under my proposed Ornithologists are encouraged to re-examine the 
interpretations of the H-P system, there is a fixed modifications to the H-P system proposed by 
point to start a nomenclature of molts and Howell et al. (2003) and to resolve existing 
plumages (i.e., commencement of the initial conflicts in North American molt terminology by 
acquisition ot contour leathers) and all birds have adopting the proposed interpretations of the H-P 
the same numbered prebasie and prealternate system described in this paper, 
molts, and basic and alternate plumages. Thus, 
the four molt strategies may be attributable to 
variability in conventional first prebasie and first 
prealternate molts. 
Further Study 
Humphrey and Parkes (1959, 1963) were aware 
that some bird species have molt patterns that are 
difficult to describe using their molt terminology. 
Subsequent studies have identified more of these 
molt patterns, including the repeated wing molts 
exhibited by many tern species (Bridge et al. 
2007) and the continuous molts of feathers on the 
head of the Field Sparrow [Spizella pusilla) 
(Willoughby 1989) and the southern subspecies 
of the Black-chinned Sparrow ( S. atmgularis 
atrogularis) (Tenney 1997). Humphrey and 
Parkes (1959. 1963) believed a thorough under¬ 
standing of the typical molt patterns exhibited by 
the substantial majority of birds will help us 
understand the evolution of atypical molt patterns. 
Humphrey and Parkes < 1959) acknowledged that 
further study of molts and plumages may indicate 
the need to alter or broaden the H-P system. 
However, based on current knowledge of the 
complicated and highly variable molt and plumage 
cycles, it does not appear necessary or advisable to 
do so at this time, except through adoption of the 
proposed interpretations of the H-P system de¬ 
scribed in this paper. This approach is consistent 
with the fundamental purpose of Humphrey and 
Parkes (1959). which was to facilitate a search for 
the evolutionary b;isis of av ian molls and plumages 
by treating similar molt and plumage sequences in 
various groups of birds as provisionally homolo¬ 
gous until scientific studies revealed that it was 
inappropriate to do so. In contrast, Howell et al. 
(2003) contradict the fundamental purpose of the 
H-P system and impede the search for homologies 
involving the conventional first prebasie moll by 
deeming this molt a unique preformative molt. 
Proponents of changes to the fundamental purpose 
and presumed homologies of the H-P system bear 
the burden ot providing supporting scientific 
studies. Howell et al. <2(X)3) did not provide such 
evidence, and their proposed modifications to the 
H-P system are premature and unnecessary. 
ACKNOWLEDGMENTS 
I thank E. J. Willoughby, Peter Pyle, and five anonymous 
reviewers lor reviewing and commenting on ihis paper 
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