[jewill]

I wonder it it was even legal for these Surrey birds to be planted there by humans, as I am pretty sure they were. It would be interesting to discover how they got there.

(Don't misunderstand me, I am not trying to make trouble, just wanted to contribute my view).

Although this is not based on fact (not that I’m aware of) and is only a guess on my part...the area that the birds are in now used to be undeveloped and, for the most part, farmland. This was only about 20 years ago. I’m assuming that the original flock was part of a hobby farm and they were abandoned when the developers swooped in. Another example of non-native birds being introduced to an area. At least these guys don’t appear to be having any impact on native birds (not yet anyway), not like the European Starling or the Euarasian Collared-Dove, to name just two.
And, from one senior to another, we have earned the right to make a little trouble now and then don’t you think?