Another sight that presages spring's arrival

Driving to Łódź today, I spotted this gaggle of migrating geese overhead. It has long fascinated me as to why they keep this 'V' formation and how the lead goose comes to be selected. This article has the answer to the first question - it's to do with aerodynamics (akin to cyclists following in one another's slipstream). One goose may not make a summer, but a large flock like this suggests that spring is on its way. The temperature nudged +14C today - a record so far this year.