Hawkins • THE 'FIRST BASIC PROBLEM' REVISITED 
415 
basic plumages in many birds, including most 
Passeriformes and Charadriiformes, are analogous 
and not homologous. Howell et al. (2003: 637- 
638) also maintained these plumage similarities 
"cloud an appreciation of homologies'' between 
juvenal and definitive basic plumages and their 
underlying molts, which are anything but clear. 
Howell et al. (2003) supported their position by 
citing examples in which plumage color and 
pattern, when considered in isolation, may 
provide a misleading indication of the underlying 
molt, i.e., shorebird species that variably exhibit 
delayed plumage maturation and a tropical 
African passerine whose basic plumage may 
resemble its alternate plumage when conditions 
are favorable for breeding. These examples do not 
justify a categorical exclusion of plumage color 
and pattern in molt homology analyses, or a 
position that widespread similarities in conven¬ 
tional first basic and definitive basic plumages are 
not suggestive of homologies between these 
plumages and their underlying molts. Howell et 
al. (2003:638) acknowledged the physiological 
processes that govern molt and plumage color and 
pattern “usually are coincident”, and these 
processes usually produce the expected result in 
terms of the color and pattern of the resulting 
plumages. Thus, we may validly presume that 
similarities in plumage color and pattern generally 
are suggestive of underlying plumage and moll 
homologies. Plumage color and pattern, as 
Thompson (2004) showed hypothetically and 
other ornithologists have demonstrated in actual 
molt homology analyses (e.g.. Oring 1968, 
Heitmever 1987, Thompson and Leu 1994), may 
provide critically-important information in a molt 
homology analysis. This does not mean plumage 
color and pattern are infallible or should be given 
priority over other relevant factors in a molt 
homology analysis (e.g.. timing and extent), but 
neither should they be rejected without good 
reason. This analysis is consistent with the H-P 
system (Rohwer et al. 1992. Thompson 2004). 
Proposed Solution to the ‘First Basic Problem' 
The fundamental purpose of the modifications 
to the H-P system proposed by Howell et al. 
(2003) was to address the 'first basic problem'. 
This 'paibletn' may be addressed in a manner that 
does not require recharacterization of the pre- 
juvenal and conventional first prebasic molts and 
resulting plumages as proposed by Howell et al. 
(2003). Specifically, under the H-P system the 
conventional first prebasic molt should be con¬ 
sidered potentially present and included for 
purposes of numbering prebasic molls even when 
it is absent (Fig. I). Thus, for example, a species 
of eagle that does not have a conventional first 
prebasic molt commences a molt cycle 1 year 
after hatching w ith a second prebasic molt and not 
a first prebasic molt, which is absent and should 
be noted as such in any detailed description of this 
species' molts and plumages. 
This approach also applies to the first pre¬ 
alternate molt and addresses a similar ‘first 
alternate problem’. Thus, in species that have a 
prcbasic-prealtcmate-prebasic definitive sequence 
of molts but lack a first prealtemate molt (Pyle 
2008). the prealtemate molt that occurs after the 
second prebasic moll is the second prealtemate 
moll despite the absence of a prealtemate molt in 
the first molt cycle (Fig. I). 
Definition of the First Molt Cycle 
Howell et al. (2003:639) stalled the first molt 
cycle with “the attainment of juvenal plumage” 
because they maintained the first molt cycle under 
the H-P system starts with the highly-variable 
conventional first prebasic molt. Humphrey and 
Parkes (1959, 1963) did not address this point, 
however, and the H-P system does not require this 
molt be the starting point for plumage succession. 
The position of Howell et aL (2003) that the first 
molt cycle starts with completion of the pre- 
ju venal molt appears inconsistent with the H-P 
system because, under this system, all molts are 
named in reference to the incoming contour 
feathers and defined by the beginning of a molt 
and not its completion. 
1 suggest the first molt cycle under the H-P 
system should include a bird's first acquisition of 
contour feathers, and thus propose that the first 
molt cycle begin with commencement of the initial 
acquisition of these feathers. In the case of birds 
with a natal down, or all birds under the definition 
of ‘molt’ in Howell et al. (2003), this starting point 
is commencement of the prejuvenal molt. This 
approach provides an unambiguous starting point 
for the first molt cycle for all birds with the 
possible exception of the Bam Ow l (Tyio alba) and 
any other Tytonidae in which natal down may 
effectively constitute the juvenal plumage (Marti et 
al. 2005). However, this issue is not solved by 
starting the first molt cycle w ith the attainment of 
juvenal plumage because one still must identify the 
juvenal plumage for this purpose. 
