i still say that the bird is a spying device. after all it was intently watching the match even through the intense chakra, flying stones, flying stars, flying bodies, flying dust... and then it flies off after naruto beats neji? kinda suspicious isn't it?
i guess maybe it DID symbolise something to Neji after he was K.O.ed by Naru-kun but its probably a henge kage bunshin no jutsu from either jiraiya or kakashi