Life‐history consequences of partial‐moult asymmetry

• Published in: Journal of Animal Ecology
• Main Authors: Brommer, Jon E., Pihlajamäki, Outi, Kolunen, Heikki, Pietiäinen, Hannu
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2003
• Subjects: Ural Owl
• Online Access: http://dx.doi.org/10.1046/j.1365-2656.2003.00773.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1365-2656.2003.00773.x; https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2656.2003.00773.x

Summary Experiments have shown that asymmetry in flight feathers reduces flight performance. Large birds moult only part of their flight feathers during one season. We explore the asymmetry in the pattern of partial moult of flight feathers. We compared the partial‐moult pattern of all 10 primary and the 10 outermost secondary feathers on the right vs. the left wing of 327 Ural owl females. We counted the number of asymmetrically moulted feather positions. The number of feathers moulted affects the potential asymmetry in partial moult. We used bootstrapping to correct for this dependency. Females moulted especially their primary feathers, but also their secondary feathers, more symmetrically than expected by chance. Ural owls moulted fewer feathers after breeding than after not breeding, but the moult pattern was not more asymmetric than expected by chance. Partial‐moult asymmetry did not correlate with current reproductive output (laying date), but the asymmetry in primaries was associated with a reduced probability to survive to the next breeding season. Developmental homeostasis in partial moult appears to be under stabilizing survival selection. Partial‐moult asymmetry may link current reproductive expenditure to the next season and may serve as a tool for biomonitoring populations of large birds.