The fishermen were out in force by the time we arrived at Pinchbeck ponds, the promise of day-long sunshine and the children on school holidays bringing lots of people out. We walked up to the top pond, the more natural of the four and the least used for fishing. An angler landed a small perch as we passed; its striped flanks and orange fins glistening silver in the bright light. Further on, as we rounded the two yew trees, we disturbed a water vole out on the bank.

It quickly scuttled back into the water, disappearing with a characteristic "plop". Examining where it had been we found feeding signs, two to three-inch lengths of rush and grass. Why don't they eat all of it? A small latrine of droppings was beside the feeding signs - not a fully fledged territory marker, trampled and scent-marked, so perhaps our vole is a male.

A single narrow, worn track in the grass led away, along the bank and towards the trees. Using them as cover, we watched to see if the vole re-emerged. While waiting, we noticed that two long-tailed tits were making regular trips to the trees, beaks full of downy willow seed and that of bulrush. They came every five minutes or so, always together.

After a deal of peering through the evergreen branches we were able to spot the four-inch deep, two-inch diameter tube of lichen, moss and seeds which they had fashioned into their nest. The only time they stopped calling to each other was when inside the nest, working the latest load of material into place. The nest is such a snug fit that they have to fold their tails over their heads when inside.

Turning back to the bankside, the water vole was swimming along the water's edge towards us. Startled, it dived down, kicking up mud from the bottom, and disappeared into an entrance below the water to its burrow system.

The spring sunshine has brought out those butterflies that hibernate as adults. We were treated to peacock and small tortoiseshell, with a real added bonus, a sulphur yellow brimstone fluttering along the hedge boundary.