This time of year is a great time for observing the golf course. As things slowly wake up drastic differences can often be observed that would otherwise be hidden in the flood of green that always comes in April.
We have earthworms on all parts of the course especially the tees, fairways and rough. There are naturally less earthworms on the putting greens as they are almost pure sand with very little organic matter for the worms to feed on.
Some people consider earthworm castings a nuisance as they can detract from the "perfect" look of a fine turfgrass surface. I see the castings as a sign of a healthy soil and a huge benefit to the entire golf course ecosystem. The trade off is small. A slight imperfect look that most people don't notice for a free source of nutrients and soil aeration. The worms are also a source of food for many birds that frequent the course.
There are many insect and soil borne pests that frequent the golf course. Many that consume turf roots and cause turfgrass death. All the earthworms do it feed your turf and aerate your soils. What's the problem?
To me this kind of natural activity is the true definition of sustainability on the golf course.