If you see birds here in March throwing themselves back and forth in wild displays of tumbling flight manoeuvres, calling loudly, you are lucky enough to be watching lapwings who have returned here from their winter quarters. The males defend their territory or, later, their young from birds of prey with these swooping flights - also called 'acrobatics' . Their wing beats make a booming sound. Their distinctive black and white plumage and, in particular, their long, twin-pointed crests on the backs of their heads make lapwings unmistakeable. Furthermore, lapwings are very fond of the sound of their own voices, especially in the breeding season. Their characteristic calls have given them their name in German and Dutch - as well as their alternative English name of peewit. In the Netherlands the lapwing is also the reason behind a strange tradition every year: in the spring many Dutch people go hunting eggs in the meadows and pastures - but they're hunting lapwing eggs and not Easter eggs. The person who finds the first egg is celebrated and he or she may present it to the king. After all, lapwing eggs were considered to be a delicacy in times gone by. Today, the birds are strictly protected, so the tradition has had to be modified. Today's egg hunters are protectors of the birds, accredited by a licence. Instead of collecting eggs, they mark the nests so that farmers don't drive over them, or erect protective fences so that the clutches are not trampled by livestock. This rethinking is very important because the lapwing populations in Europe have fallen dramatically in recent decades. This is because their natural habitat is shrinking. As wading birds, they prefer to breed on wetland meadows, the edges of bodies of water, pastures or marshes because this is where they find plenty of insects, worms, snails or larvae, and here, even the young leaving the nest can look after themselves here. But nowadays there are ever fewer wetland meadows and extensively farmed grazing areas. As in many places, here, too, the groundwater level has fallen drastically in recent decades because the straightened Rhine is flowing more quickly, carries along more gravel from the bed and thus digs deeper into it. In turn, the drier meadows are being farmed more intensively, and the use of herbicides removes flowering weeds, thus eradicating insects that are a source of food, and many pastures have disappeared completely because the dairy cows are kept in their byres. A particular threat to the populations is mowing the meadows too early, which destroys the clutches of eggs. This fate also affects the birds who move to arable land, such as maize fields. Most of the first clutches don't survive the relatively late sowing of the maize, and second and third clutches are usually smaller and less successful. Luckily, people here are trying to conserve the natural habitat of the birds or to enlarge it again by implementing suitable measures in the conservation area so that we will still be able to watch the entertainer of the air again in the future.