Coastal Birds Face a Growing Threat: Wildlife Disturbance

by Allison Anholt, Coastal Community Science Biologist

Oregon Coast beaches show many seasonal trends. In the spring, breeding birds seeking safe, quiet places with abundant food resources return to the coast to nest and raise young on the sand and rocks, beginning breeding in April or May and ending in August. Among these are birds that many Oregonians, even those that don’t identify as birders, know and love: artwork all over coastal towns depicts the Tufted Puffin, Common Murres gather in massive nesting colonies that are easy to view, and Black Oystercatchers have such loud voices you can’t help but notice them. But other species depend on our beaches and aren’t so easy to notice. For example, threatened Snowy Plovers are perfectly adapted to spending their entire lives in the narrow stretch between the high-tide line and the dunes on open, sandy beaches.

Two dogs on the beach disturbing a nesting Snowy Plover
Photo by John Dean.

After Memorial Day, the Oregon Coast sees another seasonal trend. Vacation season kicks off smack dab in the middle of the breeding season for these birds, at a very vulnerable time, when eggs and chicks are most subject to disturbance by people. Disturbance means the action of intentionally or unintentionally keeping birds away from their nests or chicks. Forms of disturbance include tidepooling; flying drones, kites, or paragliders; bringing dogs to the beach; or even hiking in the sand in the wrong spot—basically, a lot of the fun things we like to do at the beach! The vulnerable birds that use our coastline have evolved over thousands of years to deal with the hazards of near-constant wind, rip tides and storm surges, hot and cold weather, and predators stealing eggs and young. Only in the last century have they had to deal with a high volume of people recreating directly within their nesting areas. To a bird, a dog mimics a coyote, a natural predator. Kites or drones remind them vaguely of aerial predators like Peregrine Falcons or Great Horned Owls. Vehicles driving on beaches become an extra hazard to sand-nesting birds like Snowy Plovers because the chicks can fall into tire tracks and often can’t scramble out fast enough to avoid another vehicle. Even less active forms of recreation such as tidepooling or hiking in nesting areas can result in nest failures. Nests are well camouflaged, speckled eggs and chicks can be near invisible, and thus all are at risk of accidental trampling.

In addition to the risk of injuring or killing an adult, chick, or nest, with these actions, disturbance takes a more insidious form. When presented with disturbance, birds will initiate a fight-or-flight response—they may fly or walk away from their nest, hoping that camouflage prevents the nest from being spotted, or they may perform elaborate distraction displays in an effort to lure the perceived predator away from the nest or brood of chicks. Either response takes energy and attention, which allows “real” predators access to the eggs or chicks. Crows, ravens, and gulls in particular are extremely intelligent and readily take advantage of an easy meal. Nearly two-thirds of all nests monitored in our Snowy Plover Patrol program fail due to predation, even on beaches with relatively few people. Too many disturbance interactions can cause entire colonies of seabirds like Common Murres to collapse, or fail, for the breeding season. This can have not only immediate impacts, but long-term consequences for the entire population.

Camouflaged Snowy Plover nest, photo by Allison Anholt

Because the height of the breeding season coincides with the busiest tourist season, we have an obligation to share the beach. We have a right to enjoy vacations with our families, just as these birds have a right to raise their families. So how can we all successfully use the same space?

Obey Signage and Posted Rules

Fortunately for people, birds are not equally distributed across the entire coastline. Snowy Plovers, for example, are far more likely to be at river inlets and in areas where the beach is particularly wide and flat. Most of these areas are protected by the Habitat Conservation Plan, a legal document outlining the path forward to increasing their population and de-listing these birds from the Endangered Species Act. These areas stretch in small sections across fifteen sandy river inlets on the Oregon Coast, each of them marked by Oregon Parks and Recreation Department (OPRD) with diamond-shaped signs restricting human recreation to passive forms such as hiking or horseback riding in the wet sand, where plovers won’t nest. Black Oystercatchers, conversely, only nest on rocky outcroppings. New this season, Bird Alliance of Oregon and partners at OPRD and U.S. Fish and Wildlife have worked to design signs that will be placed near particularly vulnerable Black Oystercatcher nests, identified by volunteers in our Black Oystercatcher Monitoring Program, in order to reduce human disturbance.

Leash Your Dog

Since birds don’t read signage (though we wish they would!), we can’t predict exactly where they will show up and protect all possible areas. Dogs not only mimic coyotes and scare adults, they use their powerful noses to scout out camouflaged eggs and chicks. Other wildlife also benefit from leashed dogs: flocks of migratory shorebirds, creatures found in tidepools and on the tideline, and loafing seals.

Pay Attention to Signals

If you see a bird running or flying around you and peeping, be alert! This distraction display is performed only if you’re right next to a nest or a chick. If you see this behavior, try to back away carefully (while looking down at your footprints!) and give them a buffer of at least 100 feet.

Snowy Plover protecting young, photo by Terri Neal

Take Trash with You

Crows, ravens, and gulls are just as happy to raid bird nests as they are to eat trash left by people. Trash on beaches attracts these predators and results in a disturbance response.

As you recreate this summer, please think of the birds that depend on our coastline. Our resident breeding birds thank you!