INVESTIGADORES
REBOREDA Juan Carlos
congresos y reuniones científicas
Título:
Delayed plumage maturation in the tawny-bellied Seedeater (Sporophila hypoxantha)
Autor/es:
FACCHINETTI, C.; DI GIACOMO, A.G.; MAHLER, B.; REBOREDA, J.C.
Lugar:
Campos de Jordao, Brasil
Reunión:
Congreso; XXV International Ornithological Congress; 2010
Institución organizadora:
International Ornithological Committee
Resumen:
Differences in avian and human visual systems sometimes conceal plumage color differences to
the human eye that are however perceived by birds. The tawny-bellied seedeater (Sporophila
hypoxantha) is sexually monogamous and dichromatic species, but it is virtually impossible for
the human eye to distinguish between females and juveniles. We analyzed plumage maturation in
this species using reflectance spectrometry. We captured 52 individuals at Formosa Province,
Argentina, and maintained them in captivity until they completed the first post-reproductive molt.
We analyzed plumage coloration in three groups: adult males, females and juvenile males. All
individual were sexed genetically. We took measurements on four body parts (throat, breast, belly
and crown) and calculated four spectra variables (brightness, UV-blue chroma, green chroma and
red chroma). Spectrometrical analyses confirmed color differences observed between adult male
and female plumage, and unveiled color differences between the plumage of females and
juvenile males. Juvenile males also differed from adult males throughout the first year, but this
difference disappeared in after one-year old individuals in almost every measured body region,
except for crown plumage, where they still differed from adult males in all variables except in
brightness. Our results indicate that tawny-bellied seedeaters have delayed plumage maturation
and during the first breeding season one-year old males differ from older ones. Whether females
are capable to distinguish these plumage color differences and choose males accordingly still
deserves further research.