Snowy plovers are small shorebirds that are an important part of coastal ecosystems along the Pacific Coast. They play a vital role in maintaining healthy beach habitats and face numerous threats to their survival. Understanding why snowy plovers matter and how we can help protect them is key to conservation efforts.
What are snowy plovers?
Snowy plovers (Charadrius nivosus) are small shorebirds in the plover family that live along coastlines, beaches, and at inland alkaline lakes in western North America. They are named for their predominantly white plumage on their backs and wings and dark patches on their heads. Their breeding plumage also includes black patches or bands on their necks and chests. These petite birds reach about 6-7 inches in length and weigh just 1.5-2.5 ounces.
There are two recognized subspecies of snowy plovers:
- The Pacific coast snowy plover (C. n. nivosus) is found along coastal beaches from Washington state to Baja California, Mexico.
- The interior snowy plover (C. n. tenuirostris) is found inland at alkaline lakes, ponds, and rivers in the western and southwestern United States.
Pacific coast snowy plovers are smaller and paler overall compared to their interior relatives. They are lighter in weight as well. The interior subspecies also has darker plumage and more extensive black markings.
Where do snowy plovers live?
As their name suggests, snowy plovers rely on beaches along the Pacific Coast for nesting and foraging. They prefer wide, flat, open stretches of sandy beach habitat with sparse vegetation. Prime real estate for these plovers are areas that also have tidal flats, estuaries, river mouths, and lagoons nearby. Their nesting grounds stretch from southern Washington state down through Oregon and California. Large populations breed especially along the coasts of Monterey Bay and around San Francisco Bay in California.
Interior snowy plovers nest around alkaline and saline lakes, ponds, and river backwaters in the western interior United States. Major breeding sites are located in California, Oregon, Utah, New Mexico, Texas, Kansas, Oklahoma, and Colorado. These shorebirds favor open shoreline habitats with salt encrustations and surrounding saltgrass and pickleweed plants.
During the nonbreeding season from July to March, snowy plovers can be found along the Pacific coast from southern Washington state down through Mexico. They also winter inland at lakes, reservoirs, and agricultural wastewater ponds. Large numbers of interior snowy plovers especially gather at the Salton Sea in southern California during winter.
What do snowy plovers eat?
The diet of snowy plovers consists primarily of small invertebrates. On coastal beaches, they forage for marine worms, fly larvae, beetles, small crustaceans like sand crabs, and other tiny creatures. At inland lakes and alkali flats, they prey on brine flies, beetles, grasshoppers, ants, and other small insects.
Snowy plovers employ a run-and-peck foraging strategy. They will run along the beach or shoreline, stop abruptly, then hurriedly peck at their prey. Their bills are ideally shaped for precisely picking small foods off the surface. They have specialized sensory pits on the tips of their bills to help detect prey buried under the sand or mud as well.
How do snowy plovers nest and raise chicks?
Starting in early March through late September, snowy plovers build shallow nest scrapes in the sand above the high tide line of beaches. Nests are lined with bits of shell, seaweed, wood, or pebbles. The female typically lays 2-3 buff-colored eggs with dark brown spotting in the nest. Both parents take turns incubating the eggs for about 25-33 days until they hatch.
Snowy plover chicks are precocial, meaning they are mobile and able to feed themselves soon after hatching. They leave the nest within hours and are brooded by both parents. Parents will actively defend and divert predators away from the nest area and chicks. Within a month, the chicks are able to fly.
Why are snowy plovers threatened?
Unfortunately, snowy plovers along the Pacific Coast are declining at an alarming rate and face a variety of serious threats to their survival. In 1993, they were federally listed as a Threatened species under the Endangered Species Act. Their population has continued to diminish by as much as 50% in just the last 15 years. As of 2019, there were estimated to be fewer than 2,100 breeding adults along the Pacific Coast.
Major threats to snowy plovers include:
- Habitat loss and degradation – Coastal development, beach grooming, recreational use, vehicles, and presence of non-native beachgrass have eliminated and degraded necessary habitat.
- Human disturbance – Beachgoers, off-leash dogs, vehicles, boats, fishing, and other recreation often inadvertently crush eggs, disturb nesting birds, and separate chicks from parents.
- Predators – Native and introduced predators like coyotes, foxes, falcons, crows, and gulls prey heavily on eggs and chicks.
- Climate change – Rising sea levels, increasing storms, and shrinking habitat area threaten nesting and foraging grounds.
In interior regions, snowy plovers face threats from habitat loss at lakes and rivers as well as disturbance from recreation, vehicle use, and non-native predators.
Why are snowy plovers so important to coastal ecosystems?
As a threatened species teetering dangerously close to extinction, protecting snowy plovers along the Pacific Coast is critical. Snowy plovers play irreplaceable roles in the coastal environments where they live. Here are some of the most important reasons why snowy plovers matter:
- Keystone species – They help maintain ecological balance as a top-level predator of beach invertebrates.
- Indicator species – Their population’s health reflects the overall ecosystem condition.
- Coastal habitat creators – Their nesting activities help aerate sand and incorporate organic matter into dunes.
- Seed dispersers – They scatter seeds of coastal plants that help stabilize dunes.
- High biodiversity value – Their presence indicates a high quality, healthy coastal habitat.
- Genetic diversity – Pacific Coast snowy plovers are genetically distinct from interior birds.
If snowy plovers were to go extinct, the repercussions on coastal environments would be severe. Entire beach ecosystems could destabilize and degradation could accelerate without the presence of snowy plovers.
How can we help protect snowy plovers?
While the situation may seem bleak for snowy plovers, there are meaningful actions and initiatives underway to protect them. Here are some of the main ways we can help snowy plovers survive and recover their numbers:
- Designate and conserve protected beach habitats for nesting.
- Restrict recreation, vehicles, and disturbance during nesting season.
- Control predators like foxes, coyotes, and gulls at key sites.
- Regulate coastal development and modify structures to avoid impact.
- Raise public awareness and engage communities in conservation.
- Monitor populations and study responses to management strategies.
- Support legislation and policy initiatives that protect shorebird habitats.
- Remove invasive European beachgrass that degrades native dune habitat.
- Use symbolic fencing and signage to discourage human disturbance.
- Organize volunteer nest monitoring and stewardship programs.
Some progress has been seen at sites where major recovery efforts are underway, such as Monterey Bay and San Francisco Bay in central California. But continued action and commitment will be necessary to ensure the future survival of these special shorebirds up and down the Pacific Coast.
Conclusion
Snowy plovers are charismatic yet imperiled shorebirds that fill vital roles in coastal ecosystems along the Pacific Coast. As threatened keystone species, they serve as barometers of environmental quality and help maintain healthy beach habitats through their nesting activities and predation on invertebrates. Ongoing threats from human disturbance, development, recreation, climate change, and predators have caused dramatic declines, but recovery is possible through habitat protection, public education, and dedicated conservation efforts. Each of us can play a part in ensuring snowy plovers remain an integral part of our cherished coastal environments for generations to come.
