The Cuckoo Flower (cardamine pratensis), a.k.a. Lady’s Smock, is out near me.
It is easily identified by its early blooming and four pale pink petals.
It thrives in grassy places near rivers, streams and ditches.
If seen in large numbers it is a sign of damp ground and water nearby.
Since it doesn’t like permanently wet ground, it is also a sign of grasslands that are flooded in winter and drier in summer.
Its need for damp soil means it has a preference for north-facing slopes in unshaded areas.