2018-10-01 (Day 274) Migration

So today saw a flight of birds overhead in a pretty impressive V formation. But what was interesting was that they were flying north, as if they wanted to be somewhere cold for the coming winter.

Later in the day I saw another such flight, they were perhaps going a little more towards the east than this lot, but still definitely mainly north.

So... who goes north for the winter?

PS It's October. When did that happen?