Friday, May 19, 2017

Western Snowy Plover: A Threatened Species

Western Snowy Plovers (Charadrius nivosus nivosus) are small, sparrow-sized shorebirds, found up and down the Pacific coast in decreasing numbers.  They are cryptically colored and easy to overlook, as they blend in perfectly with the sand and bits of driftwood and sea wrack of their beach habitat.  Like other plovers, Western Snowy Plovers belong to the family Charadridae, along with our more familiar and conspicuous Killdeer (Charadrius vociferous).  I personally think Snowy Plovers are one of the cutest birds around. 

Ranging from Washington to Baja California, Western Snowy Plovers forage on beaches and foredunes for very small crustaceans, invertebrates and insects.  The breeding season lasts from March through September, which unfortunately coincides with the period of heaviest use of beach habitat by tourists.  These diminutive shorebirds nest on sandy beaches and shores, at stream mouths and on coastal dunes, laying three very tiny, perfectly camouflaged eggs in small nests made of seaweed, driftwood pieces, pebbles and sea shells.  Chicks leave the nest a few short hours after hatching, and adults lead them to suitable feeding sites where they teach the young plovers to forage in the sand among washed-ashore kelp and dune vegetation. 

The sad irony is that the same defense that protects the nests from predators, cryptic coloring, makes them vulnerable to trampling and crushing by uninformed and unaware beach-goers.  Tourists, vacationers, equestrians and frolicking dogs pose a large threat to nesting snowy plovers; a child or adult can easily step on and destroy a whole nest and never know.

Each time a nesting adult is disturbed and frightened off of its nest, the parent bird loses precious energy in running or flying away.  The abandoned nest is left vulnerable to predators, burial by blowing sand, and cooling off or overheating (both of which kills the developing chicks inside the eggs after just a short time).  Human activity near nest sites can cause adults to remain away for long periods of time; a kite hovering above a plover nest is perceived as a predator (such as a hawk) causing distraught parents to abandon the nest.

In 1993, the federal government listed Western Snowy Plovers as a threatened species due to low population numbers caused by habitat loss and destruction, loss of nesting sites and increased predation.  Development and human activity along the coast has led to a precipitous decline in suitable coastal strand habitat.  Introduced species that become invasive, such as European Beachgrass and iceplant, further compound the problem by crowding out native vegetation on small fragments of remaining dune habitat.  Dunes choked with non-native vegetation lack the open spaces plovers need for nesting, and thick plant cover provides hiding places for plover predators.

Natural predators of the snowy plover include falcons and owls, along with opportunistic mammals like raccoons and foxes.  However, humans have increased the number of plover predators by intentionally introducing animals, such as red foxes, dogs and feral cats, and by unintentionally attracting animals that thrive alongside humans, like crows and ravens.  Ruthless nest predators, these corvids scavenge the wake of garbage that follows wherever humans tread, receiving an unnatural nutritional boost that leads to greater reproductive success.  More hungry corvids in the area means fewer eggs and young of threatened birds, like Western Snowy Plovers and Marbled Murrelets (Brachyramphus marmoratus )in the north, hatch and grow to maturity.

The Wild Bird Rehabilitation program at Monterey Bay Aquarium is one of the main shorebird rehabilitation facilities in Northern California, and these dedicated wildlife workers have had success with Western Snowy Plovers.  The following is a quote from their website:
"We work with local and regional parks and avian conservation groups to rescue abandoned, threatened or damaged eggs, chicks and adults during the breeding season. These are incubated and reared for release. Since 2000 we've reared and released 123 plovers at Monterey Bay beaches, including 80 that hatched from eggs."

Prior to release, Snowy Plovers are banded by Monterey Bay Aquarium.  The tiny, colored bands allow the birds to be tracked over the course of their lives.  Snowy Plovers typically return to the same beaches every year to breed, and the bands are vital to the data collection process.  California State Parks works with the U.S. Fish and Wildlife Service and bands plovers as well.  If you do see a Snowy Plover on the beach, it will most likely be sporting several colored identification bands on its tiny legs.

California State Parks estimates that Snowy Plovers nest at just over 20 sites in California, a number that has been cut in half in the last several decades.  Less than 1,500 breeding plovers are left in California, and about 2,500 along the entire Pacific Coast.  To help ensure the survival of the species, California State Parks monitors Snowy Plover numbers and breeding efforts, and closes portions of beaches from spring through fall to protect nesting habitat.  Much of the remaining habitat suitable for Snowy Plovers is on California State Parks beaches.

By following a few basic rules, you too can help the Snowy Plovers this breeding season!

Never approach plovers, nests or eggs.  Even if you don't see the birds (which you probably won't), obey posted signs and stay away from designated areas.

When you see roped off sections of beach, please, please, please respect the plovers' habitat and stay out.  Snowy Plovers, as well as their nests, eggs and chicks, are all very small and well-hidden; you probably won't see any birds or nests in the roped off area, but that doesn't mean they aren't there.  Even well-meaning people can accidentally destroy nests by stepping on them and crushing the eggs.   

Please obey posted signs and keep your dogs leashed!!

Never, ever feed wildlife.  This includes cute, innocuous-looking squirrels, bold gulls and everything else that is wild.  Feeding wildlife causes myriad problems; in this case, it attracts nest predators, like gulls, crows and ravens, that eat plover eggs.

Please clean up after yourself!!  Clean up all of your trash - and while you're at it, pick up a few extra pieces of garbage on the beach.  Human trash invites plover nest predators, like ravens, crows, foxes and raccoons; it draws them to the area, then creates an artificial source of energy, allowing them to be more reproductively successful which compounds the problem each season.  Plastic and other refuse is also dangerous and deadly for all manner of sea life (including birds).

Do not remove pieces of driftwood, sea weed, rocks or shells from California beaches.  This "junk" on the beach is part of the ecosystem and provides cover and nesting materials for Snowy Plovers.  Feel free to remove garbage: plastic bags, balloons, Styrofoam, broken flip-flops.  Help yourself!

An informative brochure from California State Parks about sharing the beach with Snowy Plovers can be found here:

Share this with fellow beach-goers!

An important postscript:  These photos were taken with a zoom lens from behind a barrier a respectful distance away from the birds.  I stayed just a minute or two.  If you see Snowy Plovers this summer, take just a minute to get your fix of cuteness and maybe snap a couple of photos.  Don't hang around the birds or try to get closer.  And for goodness sakes, don't ever chase or pursue a plover for a better photo!  You may do more harm than you will ever know. 

Appreciate these little guys from a distance, then let them get back to the task at hand, which is, hopefully, raising a small brood of young: just one part in ensuring the survival of this species.

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