Photography and text by Sarah Killingsworth
Matt Lau is scanning for tiny beige spots in a sea of sand.
For the past nine years, Lau, a National Park Service wildlife biologist, has been playing this beachfront Where’s Waldo at Point Reyes National Seashore during spring and summer. He’s looking for western snowy plovers (Charadrius nivosus nivosus) and their nondescript nests, hidden in scrapes in the sand just above the tideline. His goal: to help them survive.
These birds are so well-camouflaged that an unwitting person could easily walk right through their nesting area—destroying their minimal nests and dun-colored eggs.
Finding the nest is the key to protecting this federally threatened species. There are an estimated 2,500 western snowy plovers on the whole West Coast and the 2024 breeding population in Point Reyes National Seashore was 50 birds; it hit a low in 2012 and varies each year. Other western snowy plovers migrate through here in the winter, but most of Lau’s work focuses on the breeding plovers, which nest here year after year.
The National Park Service is charged with protecting the plovers from predators—among them, coyotes and great horned owls, as well as humans’ canine companions.
Recently, one incredibly smart predator has been going after nesting adults—adding a new challenge to protecting this species.
For the last several years, I’ve been trekking out to the beach with my camera to document Lau’s work monitoring the plovers at Point Reyes.
Mere human presence can attract ravens and other predators, so I walk in Lau’s tracks in the sand, we wipe away our footprints around nests, and he works quickly at each nest—typically a half-hour or less, even when banding chicks.
During bandings, I keep watch for predators—particularly raptors and ravens. If a black bird shows up, and seems interested in what we’re doing, we leave.
The Park Service has done a lot ^(https://www.blogquicker.com/goto/https://www.nps.gov/pore/learn/nature/birds_snowyplover.htm) for the Point Reyes plovers, like restoring dunes, stationing docents at the trailhead to educate visitors, and symbolically fencing off beach areas. The principal protection for the nests themselves is exclosures—wire cages that plovers can easily run in and out of, but that keep out the many animals that would like to eat them. Chick survival “was dismal” before these cages were added in 2002, Lau says.
But exclosures have their risks: they’re way more visible than the nests themselves. For years, NPS has been tweaking the exclosure design, and in 2022 moved to lower-profile “mini-exclosures ^(https://www.blogquicker.com/goto/https://www.nps.gov/articles/000/sfanblog_biologists-test-new-nest-exclosure-design-for-2022-snowy-plover-breeding-season.htm).” While 2022 saw a record number of fledglings, troubling losses of adults began in 2023. The exclosures that protect eggs and chicks may take their toll on adults.
Fluffballs on toothpick legs, western snowy plover chicks are mobile as soon as they hatch. Within a day, they begin to move away from the nest site, typically accompanied by their father (while their mother leaves to potentially nest again with another male). They take a month to fledge, but chicks get far on foot—traveling as far as a half-mile from the nest in just the first few days, according to Lau.
The three pale, speckled eggs in each nest rarely produce more than two fledglings. Often it’s only one, or none. Fifty nests in 2023 yielded just 19 fledglings, while in 2024, 41 nests produced a record 31 fledglings. The numbers vary each year, but historically, Point Reyes has been a population sink.
Ravens are a primary predator of the western snowy plover eggs and chicks. And often it’s humans that bring them around, with our food and our trash and our hubbub. Our off-leash dogs, driftwood structures, and nearby ranching operations can all attract ravens. And once ravens are in the vicinity, they are more likely to spot the exclosures, eggs or chicks.
Western snowy plovers use a classic distraction technique to protect their nests and offspring. When a parent perceives a threat, it races away from the nest, dragging its wings and tail in a feigned injury to divert the predator.
But as soon as plovers leave the exclosure, they’re at risk. And some ravens, it seems, are taking advantage.
Last year, 37 of 57 chicks perished, and more significantly, five nesting adults disappeared. That was a big setback for the small population. The loss of adult birds that had successfully raised fledglings in Point Reyes in the past was especially hard on Lau, who knows the birds individually by the combinations of bands they wear. Cameras were added, to help identify the cause. No raven was caught in the act, but footage showed the birds circling nearby exclosures.
In 2024, after losing two more incubating adults from nests, Lau installed additional cameras and removed exclosures from the nests in that area, hoping to protect the remaining breeding adults.
This year, a biological technician working with Lau saw a raven taking off from an exclosure and killing an adult western snowy plover. The observation was a first for Point Reyes, and possibly anywhere on the West Coast.
There have been other losses of multiple incubating adults, though. In June 2006, a Humboldt County population of plovers lost eight incubating adults in the span of a week, most likely to a nocturnal predator like a great horned owl. Managers there removed all exclosures and haven’t used them since. Since then, biologists at many Northern California locations have been hesitant to use exclosures at all. For the next season in Point Reyes, Lau will use more cameras, step up nest monitoring, and remove exclosures from areas where adults have been preyed upon.
And depending on what happens next season, the park service will consider other tactics, like killing ravens or relocating predators. That has worked well with great horned owls, for plover populations south of Point Reyes—but not with diurnal predators like peregrine falcons and northern harriers, which have just flown right back to the survey site. High priorities are reducing garbage at the beaches and ensuring that ranches clean up the dead cows and cattle-feeding areas that attract ravens.
All this work must continue, according to the plovers’ species recovery plan ^(https://www.blogquicker.com/goto/https://westernsnowyplover.org/recovery_plan.html), until the population in Point Reyes grows to 64 breeding pairs and stays there. And it’s a long way from that. Western snowy plovers evolved for a niche that we’ve changed on them—while the ravens keep adapting to it. “Generalists,” says Lau, “are going to win this evolutionary war, in the time of humans.”
For now, it seems, the plovers need us: a protector that’s at least as smart and adaptable as their predators.
If you go
Seeing Snowy Plovers
During the summer nesting season, sections of the beaches and dunes in Point Reyes are closed to protect the breeding western snowy plovers and their nests. It is easier to see western snowy plovers in Point Reyes during the fall and winter, when hundreds of birds in non-breeding flocks congregate on beaches. The best beaches for viewing them are Abbotts Lagoon ^(https://www.blogquicker.com/goto/https://www.nps.gov/places/point-reyes-abbotts-lagoon-beach.htm), North Beach ^(https://www.blogquicker.com/goto/https://www.nps.gov/places/point-reyes-north-beach.htm) and Limantour Beach ^(https://www.blogquicker.com/goto/https://www.nps.gov/places/point-reyes-limantour-beach.htm). But be careful. Winter is a high-mortality time for these birds, which face cold weather, storms, overwintering falcons, plus visitors and dogs. So, please observe from a distance and avoid disturbing the birds from their “foxholes” if they are resting in indentations in the sand.
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