Now the spring birds are really arriving, even though the wind stays chill. Last weekend I was at Great Amwell in the Lea Valley north of London, where the string of old, flooded gravel pits and reedbeds alongside the river are now a designated nature reserve.

I had hardly lifted my field glasses to look at the main lake before I saw a little ringed plover. These small waders are summer visitors that often nest on islands in gravel pits, and this one was flying and displaying itself round just such an island. In their display flight they fly very fast, tilting from side to side, and the undersides of their wings flash like silver.

They are very like ringed plovers, but luckily when they fly the two species can be distinguished fairly easily. The ringed plover has a distinct white wing-bar, whereas the little ringed has plain brown wings. Also, they call frequently in flight and their calls are like mirror images of each other. One might say that the ringed plover whistles “too-pee”, while the little ringed plover cries “pee-too”.

Altogether the lake was very different from what it had been a month before. The great flock of lapwings had gone, and there were just one or two left on the islands, probably nesting there. On the far bank there was a remarkable sight — several cormorants sitting on bulky nests in the willow trees. From being winter visitors inland, these great black birds of the sea cliffs have now become tree breeders in inland colonies, and the number of these is growing fast.

There were several other birdwatchers around, and the talk among them was of a garganey, pictured, that had been seen earlier. This is a larger relative of the teal, and comes here to breed in small numbers in the summer. I went on to a hide overlooking another small lake, and suddenly this goal of the morning appeared. It swam in a slow, stately way out of the reedbed to our left, crossed the water, and went into a reedbed on our right. It gave us a wonderful view of its bold white eyebrow and its beautifully barred flanks.

As for other summer visitors, there were now swallows, sand martins and at least one house martin flying high up against the thunderclouds. A reed warbler piped up with its rattling song from the reeds into which the garganey had swum. And as the thunderstorm broke, I heard four successive blackcaps singing in the sallows as I hurried home through the driving rain and hail.

— derwent.may@thetimes.co.uk

What to look out for:

The whimbrel is now present in small numbers on foreshores en route to its northern Scottish breeding grounds from its African winter haunts. At any range, its smaller size and striped head cannot be relied on to distinguish it from the curlew, but its repeated plaintive note contrasts with its larger relative's rich, liquid tones

— Details from Birdline, 0906 8700222 (60p a min)