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Morphology and ornamentation in male magnificent frigatebirds: variation with age class and mating status
journal contribution
posted on 2023-06-08, 07:11 authored by Vinni Madsen, Torben Dabelsteen, Daniel Colaco OsorioDaniel Colaco Osorio, José Luis OsornoMale magnificent frigatebird (Fregata magnificens) ornamentation includes bright iridescent plumage and a red inflatable gular pouch. These signals are displayed during courtship, along with a drumming sound produced through specialized beak clackings resonating in the gular pouch. The extent of white in the plumage identifies three age classes of nonjuvenile male. Here we investigate how morphological and secondary sexual traits correlate with age class and mating status. Even though several age class–related differences in morphology and visual appearance can be identified, the only features that significantly predict mating success are acoustic components of courtship display. Specifically, males that mate drum at lower fundamental frequencies—that is, they have larger gular pouches—and have a quicker and more constant drumming cadence than unsuccessful males. The fundamental frequency decreases with age class, reflecting an increase in gular pouch size. This implies that females prefer older or possibly more experienced or viable males. Drumming cadence speed and stability might reflect male stamina. Apart from the acoustic differences with mating status, there is a nonsignificant tendency for back-feather iridescence to be of shorter reflectance wavelength spectra in mated than in unmated males, which, when combined with acoustic variables, improves prediction of age class and mating status.
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Publication status
- Published
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- Published version
Journal
American NaturalistISSN
0003-0147Publisher
University of Chicago PressExternal DOI
Issue
S1Volume
169Page range
S93-S111Department affiliated with
- Evolution, Behaviour and Environment Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2012-02-06First Open Access (FOA) Date
2018-08-02First Compliant Deposit (FCD) Date
2018-08-02Usage metrics
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