Based on the very fresh and rounded tail feathers this is an adult. First-winter birds have more pointed and worn tail feathers at this time of year. There is a slight possibility that it is a first-winter bird which has lost and replaced all the tail feathers, but the primaries appear to be in a similar condition indicating that they are the same age as the tail. On plumage, this is a female.
One of my favourite birds...
This pretty much works for all emberiza buntings at this time of year with the notable exception of Yellow-breated Bunting for which first-winters replace the tail and four outer primaries prior to southwards migration.
[ Last edited by lpaul at 16/11/2012 09:35 ]