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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.


Changes in the extent of black plumage in SY males. Mean (±SD) area (mm2) of black breast plumage (standardized by wing length) for SY males captured in Fall 2008 and Spring 2009. Individuals experimentally plucked and recaptured the next season (n = 4) exhibited substantial increases in the extent of black breast patches, compared with control birds captured in fall (n = 13) and spring (n = 1), as well as two unmanipulated birds captured in spring only, each of which had no experimentally plucked feathers. One control bird originally banded in fall and recaptured in spring exhibited no change in the extent of black breast plumage.
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fig05: Changes in the extent of black plumage in SY males. Mean (±SD) area (mm2) of black breast plumage (standardized by wing length) for SY males captured in Fall 2008 and Spring 2009. Individuals experimentally plucked and recaptured the next season (n = 4) exhibited substantial increases in the extent of black breast patches, compared with control birds captured in fall (n = 13) and spring (n = 1), as well as two unmanipulated birds captured in spring only, each of which had no experimentally plucked feathers. One control bird originally banded in fall and recaptured in spring exhibited no change in the extent of black breast plumage.

Mentions: For black (melanin-based) plumage regrowth in SY males, we recaptured one control bird and four birds that were experimentally plucked in fall (Figs. 2B, 5). The extent of black breast plumage from experimental birds (n = 2 in mangrove, two in scrub) showed between a 10×-107× increase in black breast plumage overall (Figs. 2B, 5). The one control recapture (mangrove) exhibited virtually no change in black breast plumage (0.49 fall, 0.39 spring). In addition, all experimental birds exhibited markedly more ASY-like black plumage than two subsequent unmanipulated birds caught in spring but not in fall (0.05 and 0.9, respectively; Figs. 2B, 5).


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)

Changes in the extent of black plumage in SY males. Mean (±SD) area (mm2) of black breast plumage (standardized by wing length) for SY males captured in Fall 2008 and Spring 2009. Individuals experimentally plucked and recaptured the next season (n = 4) exhibited substantial increases in the extent of black breast patches, compared with control birds captured in fall (n = 13) and spring (n = 1), as well as two unmanipulated birds captured in spring only, each of which had no experimentally plucked feathers. One control bird originally banded in fall and recaptured in spring exhibited no change in the extent of black breast plumage.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig05: Changes in the extent of black plumage in SY males. Mean (±SD) area (mm2) of black breast plumage (standardized by wing length) for SY males captured in Fall 2008 and Spring 2009. Individuals experimentally plucked and recaptured the next season (n = 4) exhibited substantial increases in the extent of black breast patches, compared with control birds captured in fall (n = 13) and spring (n = 1), as well as two unmanipulated birds captured in spring only, each of which had no experimentally plucked feathers. One control bird originally banded in fall and recaptured in spring exhibited no change in the extent of black breast plumage.
Mentions: For black (melanin-based) plumage regrowth in SY males, we recaptured one control bird and four birds that were experimentally plucked in fall (Figs. 2B, 5). The extent of black breast plumage from experimental birds (n = 2 in mangrove, two in scrub) showed between a 10×-107× increase in black breast plumage overall (Figs. 2B, 5). The one control recapture (mangrove) exhibited virtually no change in black breast plumage (0.49 fall, 0.39 spring). In addition, all experimental birds exhibited markedly more ASY-like black plumage than two subsequent unmanipulated birds caught in spring but not in fall (0.05 and 0.9, respectively; Figs. 2B, 5).

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.