Local Resources competition and sex ratio variation in birds

We take issue with a recent study by Gowaty (1993) that finds evidence in support of the idea that fledgling sex ratios in birds are influenced by Local Resource Competition. After controlling for the lack of independence among species due to shared phylogeny, we show that the relation between fledgling sex ratio and natal philopatry in birds is far from statistically significant. From a theoretical perspective, the documented low rate of natal philopatry in birds also makes it unlikely that parents and their offspring will often compete for resources on the breeding grounds. Thus we argue that there is neither empirical nor theoretical support for the LR.