Highways of the sky: Why birds ancient routes are under threat

Migratory birds rely on fragile flyways linking wetlands, coastlines and feeding grounds across continents. [File Courtesy]

You might have looked up and wondered how a bird, weighing only a few grams, manages to navigate thousands of kilometres across continents to land on the shores of Lake Victoria, or Elementaita. These birds, known as migratory birds, cross some of the world’s most unforgiving environments, driven by an ancient instinct to survive.

Over the past weekend, communities celebrated World Migratory Bird Day to honour this natural wonder and to recognise the ‘highways of the sky’, the invisible flyways that make these epic journeys possible.

Flyways, also known as flight paths, are a critical chain of wetlands, rangelands, and coastlines that must remain healthy for migration to succeed.

Observed in May and October, World Migratory Bird Day matches the peaks of migration in each hemisphere. During these periods, communities take part in the celebrations through birdwatching and citizen science, where everyone is encouraged to watch the birds and record them through eBird, a database for tracking observations globally. Every observation adds to the data that conservation depends on.

In May, species along routes such as the African–Eurasian Flyway leave the warmth of Africa and travel north to nest.

According to Dr Paul Matiku, Executive Director of Nature Kenya, Africa plays a central role in keeping the shared routes alive.

 “The health of our wetlands, rangelands and coastlines matters far beyond our borders. When we protect these habitats, we protect birds, biodiversity and the communities that live alongside them,” Dr Matiku said.

Birds use the flyways to travel between breeding grounds, feeding areas and seasonal refuges. There are four major flyways on land, including the African–Eurasian, East Asian–Australasian, Americas and Central Asian.

Migratory birds also follow six marine flyways. These pathways stretch across borders and oceans, joining habitats that lie thousands of kilometres apart. In between their flights, migratory birds have stopovers in wetlands. When a single link in this chain is broken, whether a wetland is drained for agriculture or a coastline is degraded by urban development, the consequences are felt across the entire planet.  Some species can disappear for good, such as the recent extinction of the Slender-billed Curlew.

The slender-billed curlew was a migratory species that bred in central Asia and wintered in Europe, North Africa and the Middle East. However, they have not been sighted since the mid-1990s. In October last year, IUCN declared the bird extinct. The curlew, like many migratory species, relied on various habitats and safe passage routes.

Conservationists have sounded a warning on the pressures that migratory bird species are facing. The birds carry nutrients across oceans, pollinate plants, spread seeds, and help keep crops growing and diseases in check. However, it is estimated that more than 40 per cent of bird species are now in decline.

Martin Harper, BirdLife International CEO, says the signals coming from the great migratory routes are hard to ignore. “Migratory birds connect us across countries, continents and ocean currents. Protecting the major migratory highways of the world is how we reverse those declines. And when we do, people gain too: cleaner water, food security, flood protection, and more resilience to a changing climate,” Harper said.

He said that although migration is one of the wonders of the natural world, it faces challenges that require international cooperation.

“Protecting flyways helps bring birds back. It also brings real benefits to people: healthier wetlands, more reliable food, and stronger resilience as the climate keeps shifting,” he noted.

One of the world’s most important migration systems is the African–Eurasian Flyway, which links Africa, Europe and Asia. Along this route, birds travel from the Arctic to southern Africa and back again. Every leg of the journey depends on a chain of healthy wetlands, coastlines, estuaries and inland habitats.

Among the species that use these routes are the white storks, which are famous for returning to the same nest year after year. Flamingos, whose movements track the health of wetland systems, also depend on these wetlands.

This year, Kenya will host the Global Flyways Summit, a first on the continent. Co-hosted by BirdLife International and Nature Kenya, the Global Flyways Summit will bring together leaders from science, policy, finance, business and civil society. Together, they will agree on the action needed to protect migratory birds and the ecosystems they depend on.

“It is especially meaningful that the Global Flyways Summit will take place in Nairobi this September,” Dr Matiku said

During the event, scientists will launch the new edition of the State of the World’s Birds report, with a focus on flyways. The report will offer the latest picture of bird populations and what they reveal about the health of nature.