Will the early bird get the mate? Egg lay order influences neural development in European Starling chicks

We investigated the role of egg lay order on growth and neural development in pre-fledgling European Starlings, Sturnus vulgaris. Chicks hatched from early-laid eggs had larger relative RA volumes than chicks hatched from later-laid eggs. There were no relationships between lay order and the volume of other brain regions, or chick growth metrics. In adult birds, RA volume is related to song repertoire size, and may affect mate attraction ability. Lay order effects on adult song nuclei should be examined further.