The Art of the Western Snowy Plover's Nest
Unlike most beach-nesting shorebirds, the western snowy plover has taken nesting to the level of an art form. I have been monitoring this threatened species during the nesting season as part of my job as a research associate with the San Diego Zoo Institute for Conservation Research. Previously, I searched for snowy plover nests along the Oregon Dunes, as well as California beaches with dune habitat. Our current study site at Marine Corps Base (MCB) Camp Pendleton offers a more diverse habitat. Because of their nesting strategy, I became more intrigued with snowy plovers the more I get to work with these resilient birds.
Before the eggs are laid, the male creates some nests by making various circular scrapes in the sand and the female selects the one she likes best. I have seen some of these simple nests adorned with decorative shells, others that incorporate the available vegetation along the dunes, and even quite a few containing woody debris that can be found concentrated along the creeks. I’ve been impressed by how well the plovers use the resources—both natural and manmade—available to them. Last year, lobster traps sometimes washed up on beaches we were studying in Ventura, California and a plover used one of them as a nest site.
The lobster traps looked very much like the mini-exclosures we use to protect nesting birds from predators. Made of wire mesh and shaped like a square (with small openings so the adult plovers can exit when needed); we place an exclosure over a plover nest until the chicks hatch. Apparently, the plovers there had gotten used to the protection offered by the exclosures, and the nesting pair that used the lobster trap did indeed successfully hatch and raise their chicks.
In contrast, our study site at MCB Camp Pendleton is more remote, so the birds there must rely on the available natural resources when selecting a nesting site.
This year, we have some birds nesting along a creek. I could not believe how well one of the nests blended in with the woody debris and rocks around it—I almost did not see it at first! I feel so good when the birds’ hard work pays off and we get to see their chicks hatch. Hopefully, they will survive and continue in their parents’ footsteps.
Western snowy plovers face many challenges each day. Predators like crows and ravens, intelligent birds that are great problem solvers, are a constant threat to the plovers. It is possible that the plovers are sometimes testing out ways to keep these and other predators from locating their nests. This might seem like an obvious observation, but shrinking habitat availability in critical plover habitat can create the need for the plovers to find new ways to adapt to disturbances. It is vitally important for us as individuals to respect these birds during this busy nesting season on the beach. I look forward to more discoveries while monitoring the western snowy plovers and their chicks on the beach.
Anjanette Butler is a research associate with the San Diego Zoo Institute for Conservation Research.