In Xenopus embryos neural specification takes place by inhibition of epithelial specification, allowing blastoderm cells to continue their previously established neural determination process. This mechanism has been termed neural induction as a "default state". The understanding of this model has been completed with the identification of molecules that can block the epithelial inducers. The antagonist mechanism between epithelial signals (bone morphogenetic proteins [BMPs]) and their blocking agents (BMP antagonists) can explain the formation of the prospective neural territory and why these BMP antagonists function as neural inducers when over-expressed in Xenopus. Despite this well understood mechanism in amphibians, little information is available for other species. The formation of the neural plate by means of a "default state" mechanism in other vertebrates still lacks experimental confirmation. We present evidence that the growth factors of the BMP family are also epithelial inducers in bird embryos, and that when over-expressed they can partially block neural induction.