Lagging Needed

I walked around Seventy Acres Lake today, it was so cold that my shutter finger went numb and I couldn't take pics for a while.

I think this greylag goose is feeling chilly too, it's hiding its head under its wing like poor robin does when the north wind doth blow.

I've been looking into the etymology of greylag. The grey bit is obvious but lag has nothing to do with insulation. Some sources say that it is because these geese lag behind when others migrate, others that lag is an old name for a goose derived from the call used to move such animals along.