The Role of Wetlands in Supporting Migratory Bird Populations

They could be right down the street from your home, sitting in a nearby park or lining the banks of tour local river. Perhaps you live near the coast, your local wetland might be a salt marsh, an estuary teeming with the calls of ducks, geese, and gulls. Whether we realize it or not, wetlands are some of the most biodiverse ecosystems on the planet Earth. These wondrous waterways play an essential role in supporting our world’s wildlife, particularly migratory bird populations.

These ecosystems, which include marshes, swamps, bogs, and fens, are unique transitional zones that exist between land and water. Wetlands provide vital resources such as food, shelter, and nesting sites for millions of migratory birds, many of whom utilize them in the course of their long and arduous journeys. Obviously, the significance of wetlands extends far beyond avian life, as they are also critical to global ecological stability, but despite the necessity they provide, wetlands are as under threat as many other vital ecosystems.

Like coral reefs and rainforests, wetlands are absolutely essential to the proliferation of life on this planet. Not only do these places allow for water filtration, they are absolutely vital for the storing of atmospheric carbon, which is one of the many environmental issues that they are under threat in the first place. In this article. we will explore the vital role that wetlands play in supporting migratory bird populations. At the same time, we will examine the many threats these ecosystems currently face. Finally, we will delve into the conservation efforts that have been enacted to help preserve these essential habitats.

Wetlands as Essential Stopover Sites

We know that migratory birds frequently undertake incredible journeys that span thousands of miles. They do this for many reasons, they travel to breed, travel to avoid bad weather, or travel to find food when it is scarce. In any case, most birds migrate between breeding and wintering grounds. Along the way, these world travelers rely on wetlands as critical stopover points. These lush ecosystems give birds a sort of “truck stop” that allows them to rest, refuel, and recover.

Food Abundance

The shallow waters and muddy shores of wetland ecosystems teem with aquatic plants, insects, small fish, mollusks, and crustaceans. Wetlands are chock-full of all the various nibbles and nutrients a tired bird needs, providing an abundance of food for migratory birds on the go. These food sources are rich in nutrients and energy, which birds need to sustain them on their journeys. Sandpipers and plovers, common species that live in wetland habitats, feed on the invertebrates found in mudflats, while ducks and geese forage on aquatic vegetation and seeds.

Shelter and Safety

Though there isn’t much tree cover in your average wetland, migratory birds are not particularly large. As such, wetlands offer birds shelter and protection from predators. These animals use the dense vegetation such as reeds, cattails, and mangroves, in order to hid themselves and reduce their vulnerability during stopovers. At the same time, many species utilize wetlands as sanctuaries where they can slip away from human disturbance. This purpose becomes ever more important with each passing year, as urbanization and coastal development continues to encroach on natural habitats.

Hydration and Replenishment

Flying is hard work and though migratory birds are highly adapted to do it, they lose significant amounts of water during flight. Wetlands have readily available freshwater sources that gives birds a chance to rehydrate. Additionally, wetlands have a number of perches, outcroppings, and soft grasses that provide areas where birds can rest and recover from the physical strain of migration.

Wetlands as Breeding and Wintering Grounds

For many migratory birds, wetlands aren’t just a stopover, they are a breeding or wintering ground for migratory birds.

Breeding Grounds

Wetlands located in northern latitudes, such as those found in Canada, Scandinavia, and Siberia, often serve as prime breeding grounds for migratory bird species. Ducks, herons, and swans rely on the unique conditions of these northern wetlands to raise their young. Within these spaces lies a rich abundance of food along with a bevy of isolated habitats that offer protection to breeding, brooding birds. Thus, these ecosystems provides an ideal environment for birds that are looking to raise a family.

One example of a bird that uses northern wetlands for this purpose is the black-tailed godwit. This bird typically breeds in European wet grasslands, so it depends on these areas to lay eggs, nest, and rear its young. Many species of ducks breed similarly, one such being the northern pintail, which relies on prairie potholes in its North American homeland for breeding.

Wintering Grounds

The winter works a little differently for some birds. Those of us who grew up in temperate areas know all about how “birds fly south for the winter.” These birds head south to wetlands in tropical and subtropical regions so that they can wait out the winter. These tropical wintering grounds offer warmth and food during the colder months. Some popular winter destinations for cold-weary birds include: the mangrove forests of Southeast Asia, the Okavango Delta in Africa, and the Everglades in the United States. These vital refuges are crucial for birds escaping harsh northern winters.

The common teal is one of these birds. Teals spend their summers breeding in temperate, though chilly Arctic wetlands and their winters in the wetlands of South Asia and Africa. No sane bird would want to spend winter in the Arctic tundra, so these areas provide teals with much-needed resource that they might then survive and prepare for their return journey home to their native breeding grounds.

Threats to Wetland Ecosystems and Migratory Birds

Despite their importance, wetlands face the same environmental issues that affect so much of our natural world. In fact, due to their location as a sort of way station between terrestrial and marine habitats, wetlands are among the most threatened ecosystems on our planet. According to experts, more than 50% of the world’s wetlands have been lost due to human activity in the past 100 years. This loss not only poses severe challenges for migratory bird populations, it could also spell much more danger for humans, plants, and animals that live in the surrounding area.

Habitat Loss

The wheels of human progress march ever forward, leaving scores of crushed plants, animals, and entire ecosystems in its wake. The human-made environmental threats of urbanization, agriculture, and infrastructure development have created a dangerous trifecta. This triad of destruction is responsible for nearly all of the damage done to our planet’s wetlands. Despite being fresh waterways, wetlands are often drained by commercial farming or housing concerns. The people that don’t understand these things don’t see critical habitats that these birds rely on, they see something that in their way; they see a piece of land that’s ripe for the taking.

Pollution

Pollution is yet another huge problem that’s dealing blow after killing blow to wetland ecosystems. This pollution comes from a variety of human-derived sources. It comes from agricultural runoff, industrial waste, oil spills, and degrading plastic; which turns into insidious microplastics. All of these elements can insinuate their way into the bodies of living organisms, poisoning them or otherwise damaging reproductive and hormonal systems. When these chemicals hit the water, they degrade water quality, making wetlands less hospitable for flora, fauna, and nearby human beings. At the same time, excess nutrients from fertilizers can cause algal blooms, which deplete oxygen levels and kill off other aquatic life that birds depend on for food.

Climate Change

Another great problem is climate change, a global problem that continues to exacerbate the loss of wetlands with each passing day. Climate change causes everything from rising temperatures to a rise in sea-level rise, as well as altered precipitation and weather patterns. Coastal wetlands, such as mangroves and salt marshes, are particularly vulnerable to these effects. Meanwhile, as our wetlands continue to shrink, migratory birds lose their essential stopover sites, and many end up perishing before they can get to their final destination.

Hunting and Poaching

In some regions, humans actually hunt migratory birds as they make their way to their breeding or wintering destinations. Overharvesting of birds, especially during stopovers, can have devastating effects on already-affected populations that have already seen their habitat slowly being destroyed by human interference.

Conservation Efforts for Wetlands and Migratory Birds

The trick to protecting these valuable ecosystems is by recognizing their importance in the grand scheme of things. Wetlands face a number of threats that that conservationists, governments, and local communities are fighting to repair. Thus, these altruistic organizations have implemented various initiatives to protect these ecosystems.

Ramsar Convention

The Ramsar Convention is an international treaty signed in 1971. Dedicated to the conservation and sustainable use of wetlands, the Ramsar has gained great prominence in the international conservation community. Any Wetlands of international importance, known as Ramsar sites, are protected under the auspices of this treaty and there are over 2,400 Ramsar sites worldwide. Together, these protected wetlands cover more than 250 million hectares or land.

Restoration Projects

There are many wetland restoration projects in progress right now. Nearly all of these initiatives involve re-establishing natural hydrology, replanting vegetation, and removing invasive species. Projects like the restoration of the Florida Everglades and the rewilding of the Yellow River Delta in China are two working examples that aim to bring back biodiversity and improve conditions for migratory birds.

Protected Areas

Many world organizations have already established protected areas, such as national parks and wildlife sanctuaries, to help safeguard wetlands from development and further exploitation by humans. These areas act as safe havens for migratory birds and other wildlife.

Iconic Migratory Birds That Rely on Wetlands

To show how many birds actually rely on wetland habitats to live, migrate, eat, and breed, we have put together a rather substantial list of several iconic migratory birds.

Sandhill Crane

The sandhill crane undertakes long, annual migrations across North America. This bird relies on wetlands such as Nebraska’s Platte River Valley as critical stopover sites for roosting and resting.

Bar-Tailed Godwit

The bar-tailed godwit is an unusually-named bird that, nonetheless, holds the record for the longest non-stop migration of all birds. This animal flies from Alaska to New Zealand and the wetlands of its Alaskan home are vital for providing the species with the essential resources they will need before taking their long journey.

Siberian Crane

Though it’s not the only one on this list, the Siberian crane is one of the most endangered migratory birds in the world. Sadly, fewer than 4,000 individuals remain today. Nevertheless, this bird relies on crucial wetlands in China and India as critical wintering grounds, yet those wetlands are rapidly disappearing.

Greater Flamingo

The greater flamingo is well known for its striking pink plumage, but it too relies heavily on wetlands across Africa, Europe, and South Asia for food. These iconic birds feed on algae, small crustaceans, and plankton, all of which can be found in shallow wetland waters.

Glossy Ibis

The glossy ibis is known for its iconic iridescent plumage. This rare bird depends on wetlands in Europe, Africa, Asia, and the Americas for survival. While it stays in these marshy places, it feeds upon insects, small fish, and amphibians. Migratory populations of glossy ibis similarly rely on coastal wetlands and inland swamps to rest and refuel during long flights.

Black-Necked Stilt

The black-necked stilt is a slender, long-legged bird that inhabits wetlands in the Americas. The stilt uses wetlands in the Salt Flats of the Great Basin and the coastal marshes of Mexico as vital places for nesting, feeding, and resting during migration.

The birds listed above illustrate the diverse range of migratory species that depend on wetlands for food, shelter, and breeding. It is only by protecting these habitats that we cab ensure the continued survival of not only these iconic species but also the countless other organisms that share these critical ecosystems.

True Investigator Says…

As you can see, wetlands have and always will be, an indispensable part of our world ecosystem. These habitats provide food, shelter, and sanctuary to millions of migratory birds, as well as providing water filtration and carbon sequestering services to the environment as a whole. Sadly, these critical habitats face numerous threats, from habitat loss and pollution to climate change. But time has not yet run out on wetlands, many thoughtful humans are doing what they can to mitigate the damage we have done and protect what wetlands we have left. So roll up your sleeves and help out if you can; the birds will thank you for it!