By Caitlin Bell
Every winter, California plays host to a species of shorebird with a name reminiscent of the season – the Western snowy plover. While these charismatic birds may not come with a wreath around their necks or shiny red noses, their distinctive black facial markings distinguish them from the other snowball-like sandpipers on the beach.
Feeding and Behavior
Western snowy plovers (Charadrius alexandrinus nivosus) scurry year-round on California’s coast. In winter, over three thousand plovers gather on the mainland coast, in San Francisco Bay, and on the Channel Islands. The birds gather in flocks on spits of sand, and can often be seen foraging for small invertebrates together at the water’s edge. Individual plovers find safety and a break from the wind in driftwood or kelp roosts.
Adult birds arrive at their breeding spots as early as March, and lay eggs between April and June. To prepare for nesting, male snowy plovers create several shallow depressions in the sand and decorate them with bits of shell, seaweed, and feathers. This decoration camouflages the nest sites from predators and acts as insulation to facilitate incubation. After breeding occurs, the female will choose the nest she likes the most and lay up to four speckled eggs. Both parents take turns incubating the eggs, with the female usually incubating during the day and the male incubating at night.
Western snowy plovers use their acting skills to protect their nests. When approached, an adult will spring up and lead a potential threat away from the nest while dragging its wing and crying out — pretending to be an easy target. Once the predator is a sufficient distance away from the nest, the adult will fly off and return to the nest undetected. The eggs hatch approximately one month after being laid. Young plovers, like many shorebirds, are precocial, meaning that they can walk and find food soon after hatching. Male parents lead the chicks to feeding areas after the female leaves the area one week after the eggs hatch. One month after hatching, the chicks fledge, shedding their downy feathers and growing flight feathers. By the end of August, most chicks have fledged and are ready to migrate to over-wintering areas on the Pacific coast.
Western snowy plovers are considered to be threatened in the state of California. Since the first broad-scale surveys were undertaken in 1977 by the Point Reyes Bird Observatory, the population of the snowy plover has declined by 20 percent. This decline is thought to be caused by loss of breeding habitat, human disturbance, and predation. Snowy plovers and humans compete for the same beaches, and the plover’s breeding and nesting season coincides with peak beach season for California residents. People walking on the beach can inadvertently crush the highly-camouflaged eggs, or disturb adults from the nest. Dogs can also harm adult birds and chicks. In addition to increased human-caused disturbances and habitat loss, the plovers must also contend with their natural predators, including coyotes, raccoons, and birds of prey.
What can you do?
California State Parks suggests several easy guidelines that can be followed to reduce your impact on the Western snowy plover. First and foremost, stay out of fenced breeding areas on beaches during the spring and summer, and ensure that dogs are leashed. Second, if you flush an adult plover from its nest, retrace your steps and walk along the water until you pass the nesting area. Third, remove all trash and food that you bring to the beach so it does not attract animals that could prey on the plovers. Lastly, tell others to be cautious on the beach. With your help, more people may move their beach towel over and save some room for the snowy plover!
Photo credits (from top to bottom): Michael L. Baird, Oregon Coast Aquarium, Westernsnowyplover.org