The rollercoaster ride migratory birds go on

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The European roller is a large attractive blue bird that breeds across Europe and migrates to Africa during the northern hemisphere’s winter. It is now considered ‘Near Threatened’ by the International Union for Conservation of Nature (IUCN).

Photo: Levente Szekeres

Scientists regard the European roller as the ‘steamroller’ of migratory birds, as it represents the plight of all nomadic birds. There are a number or reasons for their decreasing numbers.

Because migratory birds travel such vast distances and inhabit a large range, they are exposed to a variety of threats. In North Africa, the rollers are hunted while making their way south. When they finally arrive in southern Africa, the birds are relatively safe in national parks and protected areas.

However, in Europe where these birds originate from, a lack of viable nesting sites and a decline in insect numbers probably has the biggest influence on European roller numbers.

Insect population crash in Europe

The most alarming cause of the European roller’s decline is the insect population crash in Europe due to the excessive use of pesticides. European rollers are insectivorous, so rely on bugs for survival. A drop in insect numbers not only implicated rollers but important ecological processes like pollination.

The increase in pesticides could be attributed to an increase in vegetable farming in Eastern Europe. “Meat prices in supermarkets are extremely competitive in Eastern Europe so many farmers have switched to farming vegetables or high-value livestock like water buffalo and Hungarian grey cattle,” explains Béla Tokody, the coordinator of the Roller Project conducted by the Hungarian Ornithological and Nature Conservation Society. This means there is less livestock to attract flies and more insecticides are sprayed on crops to keep pests at bay.

Photo: Levente Szekeres

The loss of viable nesting sites in Europe

European rollers occur in the Steppe and Mediterranean climates across Eurasia. They prefer open grassland habitats with plenty of large old trees. European rollers nest in crevices or old woodpecker holes. They also nest in burrows along riverbanks or cliffs.

Current farming practices in Europe have cut down these old trees for farmland and forestry. “The types of trees planted are fast growing and not beneficial for birdlife,” explains Tokody.” European rollers tend to avoid intensely cultivated land such as farms or forestry.”  In order to compensate for the lack of available nesting sites, the Roller Project has set up nesting boxes that the rollers are using.

The Roller Project is engaging with farmers by providing them with indigenous trees, free bird identification kits, artificial nest boxes to cultivate a sense of ownership and pride for bird species. “Some farmers are really proud to have kestrels, red-footed falcons, shrikes and rollers return to their land,” says Tokody.

Photo: Levente Szekeres

European roller migrations

Come autumn and the roller chicks have fledged the nest, the European rollers set off for Africa. “Migratory birds need to take the shortest route possible to preserve energy, says Tokody. “They also need to access resources and water whilst on route while navigating weather patterns, geographical features and other obstacles.”

Major migratory bird highways are the Straits of Gibraltar; the Central and Eastern Mediterranean, and the Adriatic. European rollers tend to avoid deserts and rainforests as they migrate. The Sahel belt is an important stopover destination for European rollers. The Sahel is an area between the Sahara desert and the beginning of equatorial Africa.

Other threats along the bird migratory routes

European rollers are not only threatened in their breeding ground but along their migratory routes too. Climate change is causing the Sahel region to heat up resulting in water bodies drying up. Insect species breed where water is found and would have provided food for the European rollers along their journey. Another threat they must contend with during their migration is bird hunting. Poorer nations like Egypt, Yemen, Libya, Sudan and Chad hunt birds for food.  Bird hunting also takes place in Saudi Arabia.  Certain sub-Saharan countries use DDT as a form of malaria control. DDT is a colourless and tasteless insecticide developed for malaria. This has a significant impact on birdlife.

“By identifying key routes, stop-over locations and threats to European rollers we can help protect migratory birds,” says Tokody. Migratory birds know no boundaries. It is going to take collaboration from NGOs and governments across Africa, the Middle East, Asia and Africa to preserve this iconic bird.

Photo: Levente Szekeres

Written by: Georgina Lockwood

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