From Open Ocean to Sandy Shores, Oceans are Bird Habitat

The Wedge-tailed Shearwater spends most of its life at sea, coming to land only to breed. Photo by Sophie Webb.

Open Ocean | Islands | Shores

Earth is known as the “blue planet” for a good reason: the ocean covers nearly three-quarters of its surface, making it the largest of all biomes. Technically, it is one ocean that covers the globe, and the names we are familiar with — the Pacific, Atlantic, Indian, and Arctic — are its basins. When we hear “oceans,” we often think of whales, dolphins, sea turtles, bioluminescent life existing in the most inhospitable of places. We think about what happens below the surface.

What we don't usually think of are seabirds, but seabirds are marine animals, every bit as ocean-dwelling as sea turtles. They spend far more of their lives at sea than on land, coming inland only for the purpose of breeding and raising young. Life on land doesn't suit seabirds the way it does other birds: their bodies are built for life on the waves. Some struggle to walk on land. But the glimpses we get of seabirds and the rare insight we have into their lives reveal secrets — and sound alarms — about the most poorly understood habitats on the planet: oceans.  

“Seabirds and humans share a perspective on the ocean unlike anything else on the planet. They have been a part of human exploration of the ocean from the start; icons of the comedy, grace, and challenge of a life at sea,” says Sea McKeon, Marine Program Director for American Bird Conservancy (ABC). “They have been our teachers of geography and guides home. They have been helping us find fish, and read the weather before we knew how to use steel, let alone a barometer. And now, more than ever, they need our help.”

Seabirds are the most endangered family of birds in the world. The ways they are struggling speak to the larger problems at work in our oceans: The flood of plastics that are now in the food chain, a changing climate forcing their ranges to shift, depleted fish stocks, wasteful fishing harvesting unwanted species that are ultimately discarded, unsafe fishing practices that harm wildlife, and marine energy development are taking their toll on seabirds. These problems are not directly connected to people and daily life on land and are largely invisible, unless we are looking for them. Seabirds bring them out of the depths and into the light. 

Many of us are best acquainted with our oceans from our perspective on the beach, where shorebirds, like the Sanderling, skitter about and Brown Pelicans fly in formation overhead. We can hardly conceptualize the vastness of the world's oceans, much less experience them as a seabird traveling thousands of miles each year. Oceans are much more than the tiny slivers we experience at their edges. Oceans, from sandy beaches to deep sea benthic environments, are habitats.

Out on the Open Ocean

Seabirds like the Black-footed Albatross (Ka'upu), Black-capped Petrel, and Thick-billed Murre spend long stretches of many months out on the water, coming to land only to nest. The wind, waves, and saltwater make the open ocean an environment that can be, at times, harsh. 

Pelagic (open ocean) birds are prepared for a life among the whipping winds and churning waves of saltwater. Specialized glands above the eyes of an albatross allow it to process saltwater, the excess salt dripping from its beak. Boasting strong and sturdy wingspans of up to 11 feet, albatrosses can soar with scarcely a wing flap. Their flight style, known as dynamic soaring, begins with a windward climb before they curve downwind and descend, where they turn once more to catch the wind. It's a kind of waving, arcing flight pattern, but their ability to make use of the differences in the wind's speed or direction, or wind shear, allows them to stay aloft and fly almost effortlessly. 

Oceans are not steady, stagnant places. They are dynamic. They have edges and barriers, places where differences in temperature, currents, salinity, and topography interact. The interaction can be as small as a phalarope's whirling pattern on the water, or where titanic oceanic currents run alongside a continent. Oceans are constantly in motion and the movement from interactions and uplift along these edges pushes nutrients up toward the water's surface (a process called “upwelling”) where light can reach. The collision of these two things — nutrients and light — is what creates abundance.

Not every part of the ocean offers this abundance. Tropical waters are beautiful and crystal clear because they lack nutrients. The Arctic in winter has high nutrients, but sunlight is missing. But both nutrients and light can be found in places like the California Current in the Pacific, or summer with the Labrador Current off the coast of Newfoundland. These areas of abundance draw seabirds, who know where to find rich sources of food to sustain life on the wing. Fishers have learned to read the currents, too.

Below the water's surface, the open oceans offer a bounty for marine birds. The largest migration on Earth is not the semi-annual journey of birds on savannas or along transcontinental flyways. Instead, it is the journey undertaken on a daily cycle by hundreds of millions of planktonic and small oceanic squids and fishes. Rising from the depths to the water's surface each night, they form the basis of most of the food consumed by marine birds. 

The connections between people and seabirds like albatrosses, storm-petrels, and tropicbirds run deep. Seabirds are wanderers, able to travel thousands of miles over stretches of oceans so vast, and that capacity for unimpeded, solo flight to the world's most remote marine environments has captured our collective imagination for centuries. But even in these places thousands of miles from land, humans leave their mark.

Over decades, plastic waste has entered the oceans, individual bottles, wrappers, bags, and countless other items that float at the water's surface. These become hazards for birds when they are mistakenly ingested and fed to young or get tangled around a bird's feet, wings, or bill. The consequences can be deadly. Plastics can seem ubiquitous in our daily lives, but reducing the amount of single-use plastics we use can make a difference. 

Unsustainable fishing practices also pose grave threats to seabirds. While we hear most often about sea turtles and dolphins unintentionally becoming the victims of “bycatch” when they are ensnared in nets, lines, and hooks, seabirds like the Waved Albatross are equally vulnerable. Some 720,000 seabirds are lost to bycatch annually. Overfishing also threatens seabirds; unsustainable take from the oceans depletes their food sources.

ABC's Marine Program and our partners are developing techniques to reduce bycatch, including using deterrents that keep seabirds clear of lines and nets, and working with fisheries to improve their operations.

On Isolated Islands, Seabirds Bring the Open Ocean to Shore

Formed from volcanic rock, the remains of ancient reefs, or land uplifted by tectonic ripples, islands emerge from the open ocean away from the continental shelf. Atolls, a type of island found in the South Pacific, are rings of islands formed by coral reefs around the edge of a volcanic island. Over millions of years, the volcano sinks and the ring of reefs rises.

Surrounded entirely by water, these masses of land are far off the beaten path, home to ecosystems that are free to flourish with little disturbance or intrusion from the outside world. Here, spectacular adaptations develop: beaks grow long and curve to fit the depth and shape of the flowers holding nectar. Feathers take on outrageous hues and lengths to please the discerning eyes of potential mates.

During the breeding season, atolls like Midway and Palmyra transform with massive colonies of hundreds of thousands of albatrosses blanketing the landscape. Seventy percent of the world's Near Threatened Laysan Albatross (Mōlī) population breeds on Midway Atoll, the long-lived seabirds returning season after season to the same spot and the same mate for decades. Their time on Midway is likely the only time they will spend on the ground. Midway is a destination for birds coming to land: Bonin Petrels (Nunulu), Great Frigatebirds (‘Iwa), White Terns (Manu-o-ku), and other seabirds nest on the atoll.

Islands are small ecosystems, but they are by no means static. They are critical stopover habitat for migratory birds, providing resources to carry on in their journeys north and south. For some species, like the Kirtland's Warbler, the islands of the Caribbean are their homes for half the year. Seabirds come in from their wanderings over the open ocean to nest, bringing with them nutrients from the prey they have taken and replenishing nutrients on land. Coral reefs benefit from their return: seabird guano improves the growth, settlement, and productivity of coral and increases fish biomass (the total quantity of an organism or organisms in a given area).

Their relative isolation makes island ecosystems incredibly fragile. Species on islands are predator-naive: when faced with new threats, like invasive free-roaming cats, mongoose, or rats, they lack the defenses needed to keep themselves safe. Even the introduction of a house mouse, weighing about as much as a golf ball, has wreaked havoc on massive albatrosses unaccustomed to their presence.

The plight of Hawai'i's honeycreepers, including the Critically Endangered Palila, illustrates the fragility of island ecosystems. At one time, more than 50 honeycreeper species could be found across the islands. Today, only 17 remain. Photo by Rob Kohley.

Hawai'i's imperiled honeycreepers provide a stark reminder of the delicate nature of island ecosystems. More than 50 honeycreeper species once thrived in forests across the islands. Today, only 17 species remain. Some are represented by fewer than 200 individuals. Colonization brought development to the islands and with it the loss of habitat, but waves of invasive species have taken a toll, too. Ungulates have ravaged vegetation and forests, avian malaria carried by introduced mosquitoes has stricken thousands of birds, and free-roaming cats and other predators have driven their numbers down further.

Plastics find their way to nests and even worse, into the bills of young birds after parents mistakenly pick them out of the water while foraging. Lights, too, can do damage: parents flying out at night to hunt can become disoriented, circling lights to the point of exhaustion. Young seabirds suffer as well. Distracted by lights when fledging, they end up grounded, making them easy prey or landing them in the path of vehicles.

ABC works with a vast network of partners throughout the Hawaiian Islands to give these imperiled and precious birds a fighting chance. Technological advances show promising results in the effort to rid the islands of deadly avian malaria. Habitat restoration of native forests, like the māmane forest on the southwestern slope of Mauna Kea home to the Critically Endangered Palila, is reversing decades of overgrazing by sheep.

Predator-proof fencing around restored natural areas like Mokio Preserve on Moloka'i's northern shore offers a glimpse of what Hawai'i once looked like, and how it can look again. The fences provide safety to nesting seabirds like the Laysan Albatross and the Wedge-tailed Shearwater (‘Ua'u Kani), species whose breeding colonies have previously been preyed upon by non-native mammals. The preserve is also an oasis in an area that has been radically altered by coastal development, where acres of habitat have been cleared to make way for houses and golf courses.

Where the Ocean Meets the Land

Ocean habitats don't end at the water's edge. The ebbs and flows of the tides and the snaking channels and estuaries that carry saltwater inland make the boundaries of the ocean much murkier, beginning with the beach. Beaches are part of the intertidal zone, where land and ocean meet. They are dynamic and ever-changing habitats where sediment is pushed and pulled by the tides and wind whips sand into dunes. 

The Red Knot is a chunky, red-breasted sandpiper with a migration journey of astronomical proportions, flying 9,000 miles north to breed and making the return trip just months later. The oldest Red Knot on record earned the name “Moonbird” because, in its lifetime, it had traveled farther than the distance of the Earth to the Moon. As if that wasn't enough, the Red Knot's migration is intimately tied to the spawning of a species older than the dinosaurs: the Atlantic Horseshoe Crab. When these ancient armored creatures come ashore to spawn, the Red Knot is there, pecking at the shoreline for the succulent eggs laid by the crabs. They are an incredible source of nutrients to power the final legs of their long-distance flights. 

The intertidal zones serve up prime foraging opportunities. Ocean waves draw in creatures from deeper waters, emerging at high tide along sandy beaches and in mudflats. Their appearance sparks a feeding frenzy for Near Threatened Piping and Snowy Plovers, along with Sanderlings and Dunlin which dart around, probing the ground with their long, thin bills. Along rocky shorelines, Surfbirds, Wandering Tattlers, and Rock Sandpipers feast on the mussels and snails left behind in tidal pools, plucking prey with their tweezer-like bills. 

We share our beaches with many species, including nesting shorebirds. Beach-nesting birds like the Snowy Plover and Piping Plover have experienced steep declines from habitat loss, natural disasters, oil spills, and other threats, making their nesting success all the more important. When you visit the beach, leave only footprints, and leave them carefully: shorebirds' eggs and chicks are remarkably well-camouflaged and easy to miss! If you come across a nesting gull or shorebird, know that they are hard at work raising their young. Give them plenty of space — at least 50 feet — and keep dogs on leashes and far away. Keeping cats indoors is critical year-round, but is particularly important in the summer when birds are nesting. The ABC-supported program SPLASh Texas works along the Gulf Coast to keep beaches litter-free and encourages beachgoers to pack out what they bring in and leave no trash behind. Plastic pollution on beaches can prove deadly for shorebirds. 

Not all coastal habitats are beaches — some are forests. Mangroves look otherworldly: these forested stands in intertidal zones possess complex networks of gnarled, tangled roots, visible above the waterline at low tide, giving the trees the appearance of being on stilts. The roots of Red Mangroves are submerged at high tide, but other mangrove trees have pneumatophores, or aerial roots, that rise out of the sediment to aid in the exchange of gas. Mangroves are workhorses in coastal ecosystems, slowing tidal waters, stabilizing and reducing erosion along coastlines, and recycling pollutants. Pelicans, egrets, and herons nest and roost in the generous branches of mangroves. The mass of roots in a mangrove stand hosts scores of invertebrate, fish, snake, and lizard species, and the mudflats exposed at low tide attract foraging sandpipers, plovers, spoonbills, egrets, and herons. 

Seabirds help keep mangroves working by bringing in nutrients in their guano, which also gets carried out by tidal waters to other habitats. Their guano contributes to the resilience of mangroves and coastal areas, creating a shielding effect that positions these habitats to withstand extreme weather. Like other coastal habitats, mangroves are at risk from the effects of climate change, rising sea levels, and the ever-present threat of development. 

Further inland are salt marshes, rough habitats where few birds actually live. These coastal wetlands flooded and drained by saltwater tides are challenging environments: the salty water is harsh, the unpredictability of the tides can make nesting a gamble. To live in the salt marsh, birds have to adapt. Larger bills help them thermoregulate, many have evolved ways to desalinate water, and some, like the Saltmarsh Sparrow, become resourceful and resilient nesters who time their nesting to the tides. If one nest gets flooded, the Saltmarsh Sparrow immediately sets to work on the next. 

Habitat loss has had a stunning effect on the salt marshes that dot the Atlantic Coast and rising sea levels have increased the volatility of a habitat that already weathers the whims of the tides. Enormous “king tides” now routinely flood the marshes for several days each month, leaving pools of water behind that destroy Saltmarsh Sparrow nests and threaten the elusive and very vulnerable Eastern Black Rail. The Atlantic Coast Joint Venture, a partnership bringing together dozens of organizations including ABC, is finding solutions to rising waters, creating openings for water to form new creeks, building up layers of peat in ditches, and even installing irrigation systems.

Take a Deeper Dive

Oceans are vast and poorly understood, but the birds that soar above the waves, return each year to islands and atolls, and eke out existences in severe saltwater environments can elucidate these little-known habitats. Seabirds are elusive, mysterious. We know little about their lives. (It wasn't until 2017 that scientists learned where the diminutive Ringed Storm-Petrel nests). But the small glimpses we get into their lives provide clues as to the state of our world's waters and enable us to see how intimately connected we are to oceans, despite our distance. Wisdom, a Laysan Albatross, is the oldest living bird on record. At least 72 years old, having logged tens of thousands of miles, she returns to shore on Midway Atoll each year, she brings nutrients from parts of the ocean most of us will ever see, and in doing so, she helps restore the land she visits only briefly. She also brings the plastic that has entered the ocean, a reminder of just how far out our actions can ripple. Oceans are closer to us than we think. 

You can make the world's oceans safer places for birds. Support ABC's Marine Program in the effort to research and implement solutions for protecting seabirds and shorebirds. When you visit a beach, make sure to share space with the shorebirds around you. Keep trash out of waterways and cut back on the single-use plastics in your life. Learn about where your seafood is coming from and support solutions to reduce seabird bycatch.