Perhaps in spring one’s thoughts should turn to the flowers of the field, as Longfellow:

I open wide the portals of the Spring
  To welcome the procession of the flowers
With their gay banners, and the birds that sing.

Which is why the 18th-century British naturalist Gilbert White is all the more remarkable in this instance, musing as he did on snail and slug:

The shell-less snails, called slugs, are in motion all the winter in mild weather, and commit great depredations on garden-plants, and much injure the green wheat….; while the shelled snail … does not come forth ’til April the tenth…. Why the naked slug should be so much more able to endure cold than it’s housed congener, I cannot pretend to say.

(Inspiration and quotes from the Oxford Book of Days)