Strength of the association between growing R₄ length and clutch size during the breeding cycle.

<p>Contouring of <i>t</i>-values associated to the effect of clutch size on LengthRe (see Methods) of females obtained in multiple regression models also including breeding stage and date at original feather removal (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096428#pone-0096428-t005" target="_blank">Table 5</a>). <i>t</i>-values were obtained from models including ranges of breeding stages centered at different median values and differing in width (see SI.5). Thus, for example, the yellow dot indicates a model where breeding stages spanning from breeding stage 10 and 21, and centered on breeding stage 15.5 were considered. Red isopletes indicate breeding stage ranges where unsigned <i>t</i>-values were significant. The arrow indicates the range where the unsigned <i>t</i>-value was largest. The apex of the triangle denotes the t-value of the models including the entire range of breeding stages (i.e. all data points) (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096428#pone-0096428-t005" target="_blank">Table 5</a>).