Who really thinks of worms as a sign of spring - earthworms that is? It certainly seems like an unlikely point to make about the bog. You won't find worms in peat, but give them some lovely leaf litter or humus, and they'll be there, taking it into their crops, grinding it up and pooping it out as soil.
Too much poopy detail?
But, spring is wet, the ground is wet, and when there is so much water it's sitting on top of the ground and flooding paths - then you will see worms in unlikely places. Suddenly they are all over the side-walk paving, the asphalt of the parking lot and even on the roads.
You will see them on the edge of the Delta Nature Reserve by the creek, and very timely too. Because worms don't just recycle dead stuff for us, giving us new and aerated soil to grow things in, but they are also food. Birds, small mammals and herptiles, emerging from their winter states and readying themselves for producing young, are happy to find this feast all laid out for them.
Earthworms - part of Spring's rich tapestry.