2011 Drought in Horn of Africa Delayed Arrival of Songbirds in Europe

The 2011 drought in the Horn of Africa not only affected millions of people living there, but also caused the songbirds to delay their arrival in northern Europe, a new study shows.

Horn of Africa is a sub-region in the African continent that comprises four countries including Somalia, Ethiopia, Eritrea and Djibouti. In 2011, Horn of Africa experienced the worst drought in 60 years, sparking a food crisis across several countries including Kenya, Somalia and Uganda.

Tens of thousands of people, most of them children under the age of five, died in the crisis. At least 10 million people were affected in the drought-hit areas.

Now, researchers from the University of Copenhagen, Denmark, have found that the Horn of Africa drought also affected and delayed the arrival and breeding of European songbirds such as thrush nightingale and red-backed shrike.

During the spring season, these birds are known to visit northern Europe for mating as well as utilizing ample food resources available. Their spring migratory route from southern Africa to the northern latitudes passes directly through the Horn of Africa. The birds make a stopover there to feed and gain energy in order to continue their travel.

For their study, the research team placed small data loggers on the backs of several birds in autumn before they began their migration to Africa. Experts retrieved the data after birds returned to Europe in spring. They were able to trace at least 26 migration routes and stopover sites of the birds. They found that the birds made a long stopover last year in the Horn of Africa, causing a delay in breeding in Europe.

However, birds that did not pass through the Horn of Africa arrived in Europe at the expected time.

"Our research was able to couple the birds' delayed arrival in Europe with that stopover in the Horn of Africa. Here they stayed about a week longer in 2011 than in the years before and after 2011. Because of the drought, the birds would have needed longer to feed and gain energy for their onward travel, causing delayed arrival and breeding in Europe," Associate Professor Anders Tøttrup, from the University of Copenhagen, Denmark, said in a statement.

"This supports our theory that migrating animals in general are dependent on a series of areas to reach their destination," Tøttrup said.

The findings of the study are published in the journal Science.