Egg shape variation across the distribution of the partially migratory fork‐tailed flycatcher <i>Tyrannus savana</i>

The evolution of egg shape across birds has been associated with breeding ecology, body constraints and nest microclimate, among other factors. We model the effects migratory status, climate, clutch size volume on variation over distribution fork-tailed flycatchers Tyrannus savana. Although status climatic variables appear to be influencing intraspecific shape, these are not significant when accounting for identity as a random factor (i.e. eggs from same more similar than clutches). Moreover, differences that we observe in explained by size. Finally, within population flycatchers, does vary respect egg-laying order and/or female wing length (standardized weight). Egg is highly variable populations but clutches, suggesting traits, apart morphology, constrain variation.