Indeed, we might well wonder: What on earth is wrong – there are fewer and fewer cuckoos around! Various studies and sightings all produce the same statistics: Many places in Europe have a dwindling population of cuckoos, a bird that was once widespread. Researchers from all over the world are searching for the answers. They're beginning to agree that several factors come into play: the food supply, climate change and hunting, which are the main reasons; People are at the root of all the problems.

Food supply

The cuckoo is known to be an insect eater, preferring butterfly caterpillars and particularly the hairy type (usually pest larvae) as these taste the best. Other birds tend to avoid this type because of their bristles since these get stuck in the stomach lining and are indigestible. Quite incredibly, this doesn't bother the cuckoo. If it gets too much in its stomach, it can "break off" the inner stomach lining and splutter it out through its beak.

As more and more pure plantations have been cultivated in recent years, especially in the lowlands, the flowering meadows and grasslands have disappeared in many places, which has meant that butterflies and moths can't find food. With the additional use of insecticides, they've been dramatically killed off. No butterflies also mean no caterpillars ...

For this one reason, the cuckoo population has tended to move increasingly into natural areas such as large nature reserves with reed belts, higher mountain valleys and alpine pastures, where the world's ecosystem is still in just as it should be.

Climate change

Host birds such as the black redstart and robin are beginning to brood earlier because the climate is getting warmer and warmer. This could also be the fate of the cuckoo and basically means that cuckoos returning from the south are encountering more and more nests eggs that already contain laid eggs. So, cuckoos arrive too late to "smuggle" their own eggs into the host bird's clutch. Sometimes, cuckoos loot nests as an "emergency measure". Depending on the species of bird, this can cause them to start laying again, which means the cuckoo can subsequently lay its eggs in time.

Persecution

Not all countries in the world operate nature and landscape conservation within the same framework as Switzerland. Italy, Cyprus and other southern countries still have illegal bird catching with locked cages and lime sticks. For example, in Malta and the Spanish Pyrenees, thousands of birds of prey and song birds are killed year after year during the migration season for fun and sport! In Egypt, conservationists discovered a market with over 400 captured and killed cuckoos, offered as a source of human food.

Money in your pocket?

So, we can still enjoy the call of the cuckoo for as long as possible and can still hear this today as it flies a distance of almost 9000km from the African savannas, depending on the weather around 25 April. So, anyone who’s superstitious should be happy because they say that if you have money in your pocket when you hear the cuckoo call, you’ll have good fortune throughout the year. Some also believe that the number of times you hear a cuckoo call in the spring determines the number of years you will live.

Based on AvS / Bert Inäbnit
Translated by Justine Hewson