Jp. Swaddle et Ms. Witter, CLUTTERED HABITATS REDUCE WING ASYMMETRY AND INCREASE FLIGHT PERFORMANCE IN EUROPEAN STARLINGS, Behavioral ecology and sociobiology, 42(4), 1998, pp. 281-287
Fluctuating asymmetry is a measure of developmental instability and re
sults from both genomic and environmental influences. Levels of asymme
try are (in part) influenced by mechanical constraints, as asymmetry i
s believed to reduce efficiency. Here we have investigated the influen
ce of habitat structure (''open'' and ''cluttered'' environments) on p
rimary flight feather asymmetry and flight performance in European sta
rlings. Our findings indicate that the increased flight demands of clu
ttered habitats act to reduce primary asymmetry and increase flight pe
rformance. These data are discussed in terms of the influence of asymm
etry on flight performance and the mechanisms that give rise to asymme
try. This study also presents a novel method, i.e., examining within-i
ndividual changes in asymmetry, by which the detrimental and positive
influence of the environment could be studied in subsequent field and
laboratory studies without confounding environmental effects with geno
mic influences.