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

Tonra CM, Marini KL, Marra PP, Germain RR, Holberton RL, Reudink MW - Ecol Evol (2014)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Migratory Bird Center, Smithsonian Conservation Biology Institute National Zoological Park, Washington, District of Columbia ; School of Biology and Ecology, University of Maine Orono, Maine.

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.

No MeSH data available.


Related in: MedlinePlus

Photographs of original and regrown feathers. A) Photographs of SY and ASY male tail feathers illustrating the color change between original and regrown feathers. SY males experienced a significant reduction in red chroma and shift in hue toward ASY-like orange coloration. ASY males displayed a reduction in brightness and red chroma, but no significant change in hue. B) Photographs of an SY male prior to breast feather plucking (left) and after feather regrowth (right).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4020684&req=5

fig02: Photographs of original and regrown feathers. A) Photographs of SY and ASY male tail feathers illustrating the color change between original and regrown feathers. SY males experienced a significant reduction in red chroma and shift in hue toward ASY-like orange coloration. ASY males displayed a reduction in brightness and red chroma, but no significant change in hue. B) Photographs of an SY male prior to breast feather plucking (left) and after feather regrowth (right).

Mentions: When we quantified the differences in color between age classes in the yellow/orange region of originally grown tail feathers, ASY (n = 43) and SY (n = 22) male feathers differed in hue, with ASY males exhibiting lower values, indicative of longer (red/orange) wavelengths (t = 11.08, P < 0.0001; Figs. 2A, 3). ASY males exhibited higher brightness values than SY males (t = −2.74, P = 0.008), but no differences in red chroma were evident (t = 0.24, P = 0.81). Upon recapture, when we examined the color of regrown feathers, we found no differences in hue (t = 1.20, P = 0.23), brightness (t = −0.31, P = 0.75), or red chroma (t = −0.06, P = 0.95) between age classes (Figs. 2A, 3).


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

Tonra CM, Marini KL, Marra PP, Germain RR, Holberton RL, Reudink MW - Ecol Evol (2014)

Photographs of original and regrown feathers. A) Photographs of SY and ASY male tail feathers illustrating the color change between original and regrown feathers. SY males experienced a significant reduction in red chroma and shift in hue toward ASY-like orange coloration. ASY males displayed a reduction in brightness and red chroma, but no significant change in hue. B) Photographs of an SY male prior to breast feather plucking (left) and after feather regrowth (right).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4020684&req=5

fig02: Photographs of original and regrown feathers. A) Photographs of SY and ASY male tail feathers illustrating the color change between original and regrown feathers. SY males experienced a significant reduction in red chroma and shift in hue toward ASY-like orange coloration. ASY males displayed a reduction in brightness and red chroma, but no significant change in hue. B) Photographs of an SY male prior to breast feather plucking (left) and after feather regrowth (right).
Mentions: When we quantified the differences in color between age classes in the yellow/orange region of originally grown tail feathers, ASY (n = 43) and SY (n = 22) male feathers differed in hue, with ASY males exhibiting lower values, indicative of longer (red/orange) wavelengths (t = 11.08, P < 0.0001; Figs. 2A, 3). ASY males exhibited higher brightness values than SY males (t = −2.74, P = 0.008), but no differences in red chroma were evident (t = 0.24, P = 0.81). Upon recapture, when we examined the color of regrown feathers, we found no differences in hue (t = 1.20, P = 0.23), brightness (t = −0.31, P = 0.75), or red chroma (t = −0.06, P = 0.95) between age classes (Figs. 2A, 3).

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Migratory Bird Center, Smithsonian Conservation Biology Institute National Zoological Park, Washington, District of Columbia ; School of Biology and Ecology, University of Maine Orono, Maine.

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.

No MeSH data available.


Related in: MedlinePlus