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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.


An after second year (ASY) male American redstart (Setophaga ruticilla; © Dennis Jarvis).
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fig01: An after second year (ASY) male American redstart (Setophaga ruticilla; © Dennis Jarvis).

Mentions: The American redstart (Setophaga ruticilla) is a migratory songbird that overwinters in the neotropics and is territorial during the winter period (Sherry and Holmes 1997). Compared with individuals in low-quality dry habitats, birds that winter in high-quality wet habitats maintain body mass (Marra and Holberton 1998; Studds and Marra 2007) and depart earlier for spring migration (Marra et al. 1998; Studds and Marra 2005). Male redstarts from high-quality winter habitats arrive earlier at the breeding grounds (Marra et al. 1998; Reudink et al. 2009a; Tonra et al. 2011) with higher circulating androgens (Tonra et al. 2011) and ultimately sire more offspring (Reudink et al. 2009a) than those from low-quality habitats. Male redstarts have colorful, carotenoid-based plumage on their flanks and tails (Fig. 1). The brightness and redness of these areas predict parental investment (Germain et al. 2010a) and breeding success (Reudink et al. 2009b,c). Offspring of males with brighter flanks are fed more often (Germain et al. 2010a). Males with brighter tails are more likely to be polygynous, and those with redder flanks are less likely to lose paternity (Reudink et al. 2009b). Furthermore, redstarts arriving to breed from more mesic winter habitats have brighter tails (Reudink et al. 2009c), which may indicate behavioral dominance (Marra 2000). Redstarts undergo a single, complete obligate molt (Sherry and Holmes 1997), but must often replace feathers adventitiously during the winter period. In winter, 10–22% of redstarts captured annually experience tail feather loss and replacement, (2008–2010; P. P. Marra and C. M. Tonra unpubl. data), and redstarts show increasing evidence of body feather replacement as winter progresses (Rohwer et al. 1983). Replacement of lost feathers is more likely in individuals that maintain or gain mass (Reudink et al. 2008), but the role of condition in the replaced feather quality is unknown. The redstart system provides an ideal opportunity to examine how winter conditions can influence plumage integral to breeding success.


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)

An after second year (ASY) male American redstart (Setophaga ruticilla; © Dennis Jarvis).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig01: An after second year (ASY) male American redstart (Setophaga ruticilla; © Dennis Jarvis).
Mentions: The American redstart (Setophaga ruticilla) is a migratory songbird that overwinters in the neotropics and is territorial during the winter period (Sherry and Holmes 1997). Compared with individuals in low-quality dry habitats, birds that winter in high-quality wet habitats maintain body mass (Marra and Holberton 1998; Studds and Marra 2007) and depart earlier for spring migration (Marra et al. 1998; Studds and Marra 2005). Male redstarts from high-quality winter habitats arrive earlier at the breeding grounds (Marra et al. 1998; Reudink et al. 2009a; Tonra et al. 2011) with higher circulating androgens (Tonra et al. 2011) and ultimately sire more offspring (Reudink et al. 2009a) than those from low-quality habitats. Male redstarts have colorful, carotenoid-based plumage on their flanks and tails (Fig. 1). The brightness and redness of these areas predict parental investment (Germain et al. 2010a) and breeding success (Reudink et al. 2009b,c). Offspring of males with brighter flanks are fed more often (Germain et al. 2010a). Males with brighter tails are more likely to be polygynous, and those with redder flanks are less likely to lose paternity (Reudink et al. 2009b). Furthermore, redstarts arriving to breed from more mesic winter habitats have brighter tails (Reudink et al. 2009c), which may indicate behavioral dominance (Marra 2000). Redstarts undergo a single, complete obligate molt (Sherry and Holmes 1997), but must often replace feathers adventitiously during the winter period. In winter, 10–22% of redstarts captured annually experience tail feather loss and replacement, (2008–2010; P. P. Marra and C. M. Tonra unpubl. data), and redstarts show increasing evidence of body feather replacement as winter progresses (Rohwer et al. 1983). Replacement of lost feathers is more likely in individuals that maintain or gain mass (Reudink et al. 2008), but the role of condition in the replaced feather quality is unknown. The redstart system provides an ideal opportunity to examine how winter conditions can influence plumage integral to breeding success.

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.