In France we also use the arrival of the swallows as a sign of spring (though they are getting rarer due to lack of nesting sites- not many barns left for them where my family is).
Up here in the Netherlands, spring is when the spring bulbs start flowering!

The daffodils and crocuses are out, but the tulips are going to be extremely late this year. Can't wait, I now work in the tulip fields area of the country.