Does (The first sign of spring) have a particular meaning?
There was a story in which an animal made a mess in a garden and destroyed the flowers and the cat's owner told:" Perhaps it's the first sign of spring."
Depending upon where you live, certain things indicate when Spring is imminent. We rely on these signs more so than the calendar, because quite often the warm Spring weather doesn't start until well after March 21. Here in Michigan, when the robins begin to return after their winter migration, we call that the first sign of Spring. Some folks use the sprouting of the first crocuses in their garden as a sign.