Open AccessPatterns of morphological variation in two sexually dimorphic bird species with different tail shapes
Author(s) -
GRÉGOIRE ARNAUD,
MCFARLANE MHAIRI L.,
FAIVRE BRUNO,
EVANS MATTHEW R.,
CHERRY MICHAEL I.
Publication year - 2007
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.2007.00808.x
Subject(s) - biology , sexual dimorphism , plumage , ornamental plant , sexual selection , range (aeronautics) , trait , cape , zoology , wing , natural selection , ecology , selection (genetic algorithm) , history , materials science , archaeology , computer science , engineering , composite material , programming language , aerospace engineering , artificial intelligence
Many studies have focused on tail ornamentation in birds, but not all tail shapes have been studied in depth. Graduated and pin tails have received less attention than forked tails, despite being more likely, in terms of aerodynamic theory, to be honest signals. We report morphological variation in live specimens of two sexually dimorphic passerines from the same site with different tail shapes: graduated (Cape sugarbird Promerops cafer ) and pin (orange‐breasted sunbird Antobaphes violacea ). Coefficients of variation (CVs) were calculated for all morphological traits, both non‐ornamental (range 1.91–5.72) and ornamental (range 5.83–21.71). Males and females did not differ in CV for any non‐ornamental trait. Ornamental traits in males of both species were significantly more variable than all non‐ornamental traits. Cape sugarbird ornamental traits were significantly more variable than those of orange‐breasted sunbirds. The high levels of variation in graduated tails relative to pintails suggest that these traits have been driven mainly by sexual selection. In contrast, both constraining natural and multiple ornament selection could be responsible for the relatively low levels of variation in pintails. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 437–443.