Climate Change Impact Threatens Habitats of Migratory Birds, New Study Finds

A flock of blackbirds search for trees to perch on in the town on Hopkinsville, Kentucky February 16, 2013. (Reuters)
A flock of blackbirds search for trees to perch on in the town on Hopkinsville, Kentucky February 16, 2013. (Reuters)
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Climate Change Impact Threatens Habitats of Migratory Birds, New Study Finds

A flock of blackbirds search for trees to perch on in the town on Hopkinsville, Kentucky February 16, 2013. (Reuters)
A flock of blackbirds search for trees to perch on in the town on Hopkinsville, Kentucky February 16, 2013. (Reuters)

The global impact of climate change is threatening the habitats of some migratory birds along their migration route in the eastern Atlantic Ocean, reported the German news agency.

Based on the findings of a recent study, the Joint Wadden Sea Secretariat in Wilhelmshaven announced Monday that the rising sea level in northwestern Europe is one of the main challenges facing migratory birds.

The Wadden Sea off the coasts of Denmark, Germany and the Netherlands is considered the hub of East Atlantic bird migration.

Millions of birds eat up food reserves for their onward flight between Africa and the Arctic in the UNESCO-listed wetland.

“Climate change affects most coastal regions. For example, in addition to sea level rise in the Wadden Sea, extreme weather events such as heavy rain and storms are increasingly affecting the resting and breeding birds,” explained Kristine Meise, program manager for Migration and Biodiversity at the Wadden Sea Secretariat.

“The consequences of climate change, for example the erosion of coasts, are already being felt in the main wintering area off West Africa,” she added.

According to the study, other factors such as overfishing, shipping, and logging have an even greater influence there.

The assessment of habitat’s exertion was part of a study published in late April.

The project has been counting migratory bird populations along the East Atlantic bird migration route every three years since 2014.

The last census in 2020 involved more than 13,000 people in 36 countries.

According to Meise, these regular statistics are of great importance to spot the changing numbers of birds in an early stage, but “the process is difficult because birds normally don’t stay in one place, and sometimes, change their flying routes. This means that one species could be shrinking in the Wadden Sea, but stable or even growing in other parts of the world.”

She noted that counting requires synchronous statistics in all the locations of those birds.

Compared to data from the past decades, the 2020 census shows an increase in the number of 83 migratory groups. The population of birds was stable in 16 percent of these groups, while the researchers recorded a decrease in 30 percent of them, such as the waders that breed in the Siberian Arctic.

Meise suggested the changing climate conditions are the culprit behind those uneven numbers.

“The migratory birds have adapted to schedules over thousands of years. Due to climate change, spring, and thus snowmelt and insects hatching in the Arctic are beginning earlier. This would result in poorer breeding and rearing conditions for young birds, and a lower breeding success.” she said.

To face these threats and preserve migratory birds, the study’s authors have called for protecting the birds’ favorite habitats and applying sustainable preservation measures.



Study Documents Extinction of 610 Bird Species, Ecological Impacts

A flock of Common Teal fly across a wetland on a winter day on the outskirts of Srinagar January 22, 2018. REUTERS/Danish Ismail/File Photo
A flock of Common Teal fly across a wetland on a winter day on the outskirts of Srinagar January 22, 2018. REUTERS/Danish Ismail/File Photo
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Study Documents Extinction of 610 Bird Species, Ecological Impacts

A flock of Common Teal fly across a wetland on a winter day on the outskirts of Srinagar January 22, 2018. REUTERS/Danish Ismail/File Photo
A flock of Common Teal fly across a wetland on a winter day on the outskirts of Srinagar January 22, 2018. REUTERS/Danish Ismail/File Photo

The Dodo, the famous flightless bird that inhabited the Indian Ocean island of Mauritius, is a case study in extinction caused by humans. The Dodo, finely adapted to its isolated ecosystem but unprepared for the arrival of people, was first encountered by Dutch sailors in 1598. Hunting, habitat destruction and the introduction of non-native species doomed it in under 80 years.

It is hardly alone. New research has documented the extinction of 610 bird species over the past 130,000 years, coinciding with the global spread of our species Homo sapiens, an avian crisis that has only accelerated in recent years and decades. For instance, the Kauaʻi ʻōʻō, a Hawaiian songbird, was declared extinct just last year.

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The researchers also revealed the ecological consequences, as the disappearance of avian species erases functions they serve in innumerable ecosystems, Reuters reported.

"Birds undertake a number of really important ecosystem functions, many of which we depend on, such as the dispersal of seeds, the consumption of insects, the recycling of dead material - for example, vultures - and pollination. If we lose species, then we lose these functions," said ecologist Tom Matthews of the University of Birmingham in England, lead author of the study published this week in the journal Science, opens new tab.

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"A good example of this is on the islands of Mauritius and Hawaii, where all or almost all the native frugivores - birds that eat fruit - have gone extinct," Matthews said.

The Dodo and Kauaʻi ʻōʻō, believed to have had fruit as part of their diets, were among those.

"Frugivory is an important function, as in eating the fruits and then moving around, birds will disperse the seeds of the plants the fruits belong to," Matthews said.

This can precipitate "secondary knock-on extinctions," Matthews said, with Mauritius now having many threatened tree species.

Most of the documented extinctions occurred on islands. Habitat loss can have huge effects given the isolation and reduced area involved, while the introduction of animals such as rats, cats and mice can have substantial impacts given the evolution of flightlessness among many island-endemic birds that left them unable to escape new predators, Matthews said.

Human hunting was a big extinction driver in the past and remains problematic in certain regions. Capturing birds for the songbird trade is a big issue, particularly in Southeast Asia, Matthews said.

Certain regions and species had more specific factors involved. For example, avian malaria, introduced by people, has triggered large numbers of extinctions in Hawaii - particularly among the endemic Hawaiian honeycreepers - where the birds possessed no natural immunity.

"The big unknown going forward is the role of anthropogenic climate change as a driver," Matthews said.

Some wondrous birds have been lost.

The large flightless elephant birds endemic to Madagascar vanished after people arrived, including Aepyornis maximus, possibly the largest bird that ever existed, about 10 feet (3 meters) tall. The flightless moa birds endemic to New Zealand, including the South Island giant moa that rivaled the elephant birds in size, similarly disappeared after humans colonized the islands.

North America's migratory passenger pigeon numbered in the billions, but was hunted into oblivion.

The 610 species combined represented 3 billion years of unique evolutionary history, the researchers said, with each lost species like chopping off a branch from the tree of life.

The number 610 is "likely a large underestimate" of avian extinctions, Matthews said, because of a paucity of data from some locales and the fact some lost species may not have left behind skeletal remains to be found. Regardless of the true number, Matthews said, "the vast majority of extinctions over the last 50,000 years are attributable to human actions."

About 11,000 bird species now exist, occupying a dizzying array of ecological niches. The researchers projected future extinctions of more than 1,000 species over the next two centuries.

"So even if you don't care about the moral and ethical concerns regarding the loss of species, these extinctions are important for other reasons, such as the loss of species that helped the environment to function effectively," Matthews added.

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