African migratory birds threatened by hot, dry weather
Africa's migratory birds are threatened by changing weather patterns in the center and east of the continent that have depleted natural water systems and caused a devastating drought.
Hotter and drier conditions due to climate change make it difficult for traveling species who are losing their water sources and breeding grounds, with many now endangered or forced to alter their migration patterns entirely by settling in cooler northern areas.
Roughly 10% of Africa's more than 2,000 bird species, including dozens of migratory birds, are threatened, with 28 species — such as the Madagascar fish eagle, the Taita falcon and hooded vultures — classed as “critically endangered.” Over one-third of them are especially vulnerable to climate change and extreme weather, an analysis by environmental group BirdLife International said.
“Birds are being affected by climate change just like any other species," BirdLife policy coordinator Ken Mwathe said. “Migratory birds are affected more than other groups of birds because they must keep on moving,” which makes it more likely that a site they rely on during their journey has degraded in some way.
The African-Eurasian flyway, the flight corridor for birds that travel south through the Mediterranean Sea and Sahara Desert for the winter, harbors over 2,600 sites for migrating birds. An estimated 87% of African sites are at risk from climate change, a greater proportion than in Europe or Asia, a study by the United Nations environment agency and conservation group Wetlands International found.
Africa is more vulnerable to climate change because it is less able to adapt, said Evans Mukolwe, a retired meteorologist and science director at the World Meteorological Organization.
“Poverty, biodiversity degradation, extreme weather events, lack of capital and access to new technologies" make it more difficult for the continent to protect habitats for wild species, Mukolwe said.
Hotter temperatures due to human-caused climate change and less rainfall shrink key wetland areas and water sources, which birds rely on during migratory journeys.
“Lake Chad is an example," Mwathe said. “Before birds cross the Sahara, they stop by Lake Chad, and then move to the Northern or Southern hemisphere. But Lake Chad has been shrinking over the years," which compromises its ability to support birds, he said.
Parched birds means tougher journeys, which has an impact on their ability to breed, said Paul Matiku, executive director of Nature Kenya.
Flamingoes, for example, which normally breed in Lake Natron in Tanzania are unlikely to be able to “if the migration journey is too rough," Matiku said.
He added that “not having water in those wetlands means breeding will not take place" since flamingoes need water to create mud nests that keep their eggs away from the intense heat of dry ground.
Non-migratory birds are also struggling with the changing climate. African fish eagles, found throughout sub-Saharan Africa, are now forced to travel further in search of food. The number of South African Cape Rockjumpers and Protea canaries is severely declining.
Bird species living in the hottest and driest areas, like in the Kalahari Desert that spans Botswana, Namibia and South Africa, are approaching their “physiological limits,” the most recent assessment by the U.N.’s expert climate panel said. It added that birds are less able to find food and are losing body mass, causing large-scale deaths for those living in extreme heat.
“Forest habitats get hotter with climate change and ... dryland habitats get drier and savannah birds lack food because grass never seeds, flowers never fruit, and insects never emerge as they do when it rains,” Matiku said.
Other threats, such as the illegal wildlife trade, agriculture, the growth of urban areas and pollution are also stunting bird populations like African fish eagles and vultures, he said.
Better land management projects that help restore degraded wetlands and forests and protect areas from infrastructure, poaching or logging will help preserve the most vulnerable species, the U.N. environmental agency said.
Birds and other species would benefit from concerted efforts to improve water access and food security, especially as sea level rise and extreme weather events are set to continue, said Amos Makarau, the Africa regional director of the U.N. weather agency.
Scientists say that curbing emissions of planet-warming gasses, especially in high-emitting nations, could also limit future weather-related catastrophes.