Integrating wildlife conservation into sustainable forest stewardship
Photo by Tristan Spinski
White-crowned Manakin (Dixiphia pipra) are small frugivorous birds that occur in the understory of lowland tropical rainforest in Central and South America. Sexes are mostly indistinguishable until the second or third prebasic molt (SPB or TPB) when males replace green plumage with a strikingly black-blue body plumage and white-crown patch. Preformative molts (FPF) are partial resulting in noticeable molt limits within the greater coverts. As a side note, the delayed plumage maturation of male White-crowned Manakin has raised concerns about the term "definitive" as described by Humphrey and Parkes (1959) whereby females would attain definitive plumage one cycle (SCB) before males (TCB). These issues potentially complicate the use of DCB age codes. To remedy this problem, Wolfe et al. (2014) suggested changing the definition of definitive to apply only to those plumages attained during definitive molt cycles; this is the definition we use when applying the WRP system. Our new definition of "definitive" was rebutted by Howell and Pyle (2014).
FPF - First PreFormative
The preformative molt (FPF) occurs shortly after leaving the nest. Note the bright-green formative plumage replacing the dull-green juvenal plumage in the median coverts. The preformative molt is partial, resulting in noticeable molt limits throughout the greater coverts (see below).
FCF - First Cycle Formative
All manakins appear to undergo a partial preformative molt resulting in noticeable molt limits characterized by replaced inner-greater coverts that are several milimeters longer than the retained and juvenal outer-greater coverts in first cycle formative (FCF) individuals. Interestingly, in the genus Manacus we find a reverse molt limit step: replaced inner-greater coverts are several milimeters shorter than juvenal outer greater coverts.
SPB - Second PreBasic
Sexes remain indistinguishable through the second prebasic molt (SPB) where the formative plumage, characterized by molt limits in the greater coverts, is replaced by a single generation of strikingly green plumage. Males sometimes acquire a few black feathers during the SPB. Also, SCB male iris color may also be more deeply colored red than FCF females, however, there is much overlap.
TCB - Third Cycle Basic
The third prebasic molt (TPB) most often results in a maturated male plumage. However, sometimes it appears that the TPB can result in mixed green and black/blue plumage allowing practitioners to identify third cycle basic (TCB) individuals.
SAB - After Second Cycle Basic
Male plumage is typically maturated after the second prebasic molt (SPB), with some exceptions (see TCB above). Because the third basic plumage is not distinguishable from subsequent plumages (4th and 5th basic plumage and so on), we can employ the "after" or "A" letter in the center position to denote we are classifying age by after a given plumage. In this case, we know the individual male is at least after the second basic plumage (SAB). Although males with maturated plumage are technically DCB, we prefer SAB due to increased precision in cohort discrimination.