nTHE spatula of the shoveler is ringed with lamellae. Thanks to the elegant workings of convergent evolution, the bills of shovelers have come to resemble those of spoonbills and flamingoes, whose bodies could not be more different but who have developed a similar means of specialist access to the smallest animal and vegetable matter in the soup of ponds and estuaries.

The strange bills of shovelers are edged on both mandibles with a fine comb - or lamella - with which they filter out snails, crustaceans and insects. The trodden-on appearance of the bill gives it a broader circumference and increases the amount they can eat. They feed with a forward tilted attitude which combines with their dumpy profile to render them both unmistakable and endearing.

In the years when our pond would flood regularly, a male shoveler spent a couple of winters with us, down on the sea at high tide or paddling unperturbed among the drowned saplings on a flooded grass field by the bowling club. With his bottle-green head, his ice-cream and cinnamon breast and those grass-green, sky-blue wing patches, down among the mallards ordinaires. Had he come from Russia like most of Scotland's winter shovelers? Or was he just down from the lochs in the arable farmland of Angus, the rich machair of Uist or the rough grazing of Orkney, where most of our summer shovelers nest in long tussocks near the waterside? He managed to look both out of place and quite relaxed.

Like all ducks, the females are cryptically coloured for concealment. In spite of this, as the illustration shows, you could not mistake a duck shoveler for any other species. By now the drakes will have moulted into their new bright feathers and taken them off to the Continent. When the Russians leave in March, we'll see our own scattering of pairs back on lowland freshwaters, wielding their spatulae as only then know how.

birdwatch