Molt Patterns, Biometrics, and Age and Gender Classification of Landbirds on Saipan, Northern Mariana Islands

Two Modes of Primary Replacement During Prebasic Molt of Rufous Fantails, Rhipidura rufifrons

“…October 2010 on Saipan (15u 129 N, 145u 459 E), a tropical Pacific island in the Northern Mariana Archipelago (Radley et al 2011). Each mistnetting station was operated for 6 hrs once every 10 days following protocols established by the Institute for Bird Populations (DeSante et al 2009).…”

“…Each mistnetting station was operated for 6 hrs once every 10 days following protocols established by the Institute for Bird Populations (DeSante et al 2009). All unbanded birds were individually marked with numbered aluminum leg bands and many were classified to age and gender (Pyle et al 2008, Radley et al 2011. Wing chord was measured (6 1.0 mm) as unflattened right wing from wrist to tip of the longest primary.…”

“…Rufous Fantails typically have a partial preformative molt and do not replace primaries or secondaries until the second prebasic molt. Age was assigned based on extent of skull pneumatization, plumage, and molt-limit criteria (Radley et al 2011), and verified through recapture data when available. Age codes were defined based on plumage cycle (Wolfe et al 2010) and birds were categorized as either second-cycle basic (SCB), including those undergoing the second prebasic molt, or definitive-cycle basic (DCB), including those undergoing the third or later prebasic molt.…”

“…Age codes were defined based on plumage cycle (Wolfe et al 2010) and birds were categorized as either second-cycle basic (SCB), including those undergoing the second prebasic molt, or definitive-cycle basic (DCB), including those undergoing the third or later prebasic molt. Individuals in breeding condition were assigned as male by the presence of cloacal protuberance or female by presence of a brood patch (Pyle 1997, Radley et al 2011.…”

“…This passerine species is insectivorous with short rounded wings and relies heavily on aerial foraging strategies. We discovered some Rufous Fantails molting bidirectionally from a center among primaries 2, 3, or 4 during research on the demography of landbirds on Saipan, Northern Marianas Islands (Radley et al 2011). Other individuals displayed a sequence more typical of passerines, commencing with P 1 and proceeding distally to P 10.…”