Color expression in experimentally regrown feathers of an overwintering migratory bird: implications for signaling and seasonal interactions

Abstract

Plumage coloration in birds plays a critical role in communication and can be under selection throughout the annual cycle as a sexual and social signal. However, for migratory birds, little is known about the acquisition and maintenance of colorful plumage during the nonbreeding period. Winter habitat could influence the quality of colorful plumage, ultimately carrying over to influence sexual selection and social interactions during the breeding period. In addition to the annual growth of colorful feathers, feather loss from agonistic interactions or predator avoidance could require birds to replace colorful feathers in winter or experience plumage degradation. We hypothesized that conditions on the wintering grounds of migratory birds influence the quality of colorful plumage. We predicted that the quality of American redstart (Setophaga ruticilla) tail feathers regrown after experimental removal in Jamaica, West Indies, would be positively associated with habitat quality, body condition, and testosterone. Both yearling (SY) and adult (ASY) males regrew feathers with lower red chroma, suggesting reduced carotenoid content. While we did not observe a change in hue in ASY males, SY males shifted from yellow to orange plumage resembling experimentally regrown ASY feathers. We did not observe any effects of habitat, testosterone, or mass change. Our results demonstrate that redstarts are limited in their ability to adequately replace colorful plumage, regardless of habitat, in winter. Thus, feather loss on the nonbreeding grounds can affect social signals, potentially negatively carrying over to the breeding period.

Malaria infection negatively affects feather growth rate in the house sparrowPasser domesticus

“…As damage accumulates, the functional properties of feathers are compromised, and hence birds must replace them. Moreover, Tonra et al (2014) showed that both yearlings and adult males American redstarts Setophaga ruticilla regrew tail feathers with lower chroma, suggesting reduced carotenoid content. Because the costs of maintaining an incomplete plumage, most birds replace these accidentally lost feathers in a process called adventitious replacement (Willoughby et al 2002), which may impose yet other costs in terms of feather quality (Dawson et al 2000, Grubb 2006.…”

Conditions on the Mexican moulting grounds influence feather colour and carotenoids in Bullock's orioles (Icterus bullockii)

“…In this species, coloration appears to have important signaling functions during both the breeding (Reudink, Marra, Boag, et al. (2009)) and nonbreeding seasons (Reudink, Studds, Kyser, Marra, & Ratcliffe, 2009; but see Tonra et al., 2014). The limited number of studies examining the potential for carryover effects to influence sexual selection by affecting ornament production is perhaps surprising given the immense body of literature on the function and evolution of plumage coloration.…”

Adventitious feather replacement favours a more rapid regeneration of primaries over rectrices in two passerine bird species

“…, Tonra et al . ). This suggests that adventitious replacement is unable fully to restore the original properties of feathers, probably as a consequence of food constraints that typically do not occur during normal moulting periods (Tonra et al .…”

“…This suggests that adventitious replacement is unable fully to restore the original properties of feathers, probably as a consequence of food constraints that typically do not occur during normal moulting periods (Tonra et al . ). The great majority of studies working on replaced feathers have traditionally analysed tail flight feathers (rectrices; e.g.…”

“…Grubb , Tonra et al . ), which apparently play a less important functional role in flight compared with other feather tracts, such as wing feathers (Jovani & Blas , Sarasola & Jovani , De la Hera et al . ).…”