Now that sunrise is close to five in the morning, it seems almost criminal to be lying in bed whilst the best part of the day slips away. For wildlife watchers it is one of the very best times. Apart from the fresh, clean air and gradually improving light, you are likely to be the first human abroad that day. At Ulley reservoir, not even the anglers were out and about.

A grey heron drifted into the shallow margins on lazy wings, then stood motionless, head cocked to one side, doing its own fishing. A coot found the fresh leaf shoots of an overhanging willow much to its liking and leapt repeatedly from the water below, neck outstretched, legs dangling, to pick off the new growth.

In the quietest corner, a pair of great crested grebes sat low in the water, guarding their newly built nest in the branches of a willow which droops into the water. The eggs, covered with weed, were well hidden; the parents kept a watchful eye on me as I passed by, which I did swiftly, getting out of their way.

The reservoir was originally built for drinking water supplies, but has not been used for this for many years. Now owned by Rotherham borough council, it is a country park where sailing, angling and wildlife conservation each have designated areas.

Although past the peak of the dawn chorus, the shrub-lined by-pass channel resonated with the song of wren, chaffinch, willow warbler, chiff-chaff and blackcap. With no background hum of traffic and other noise to muffle them, the calls are clear and crisp, filling the morning air.

Scouring the surrounding fields with binoculars, the edge of a crop of oil-seed rape came alive with rabbits and wood pigeon, whilst 100 yards to the right, a fox loped casually alongside a hedgebank.

As we were leaving, the first dog walkers were arriving. The fishing heron took off in a flurry of wing beats as a jogger passed. The sky, totally clear two hours ago, was filling with cloud. It had been the best part of the day.