Shorebird Shortage

On a gray morning, a low-tide beach walk, the sand was sans shore birds, any birds. Within the hour, one sandpiper searched the wet sand for a snack, a single seagull settled down into a dry sand seat, joined later by two new arrivals who flew in. It could have been an off time of day or year, or their time to mate offshore, or whatever, but the bigger supposition: climate change. Like many of earth’s animals, our shore creatures face differing habitat disruptions. A mix of local and global warming is shifting and shrinking our sandy beach space, where the very basic food chain supplies grow. Marine heat waves in warming ocean waters and sea-level rise are disrupting the cycles of available plankton and larval food sources, the Pacific Sand Crabs, Gould’s Wedge Clams, and some fish eat. The crabs, clams, and fish are, in turn, the food source for bigger fish and local and migrating birds.

We humans add to the problem. Coastal development, sea walls, armored bluffs are also linked to dwindling beaches. In an effort to boost back beaches, replenishment projects import sand. A good idea. But replacement sand is too often too coarse for clams, which cannot survive.

While seagulls may flock back, hungry osprey and cormorants, and migrating birds—whimbrels, godwits, surf scoters, black-bellied plovers, and curlews—may not now find enough food on our beaches as fish swim out to cooler waters. Some simply starve to death. Others, underweight due to lack of food, produce fewer chicks in their breeding grounds. In addition, the omnipresent microplastics found in almost all of the digestive systems of sand crabs tested from California beaches does not bode well for a healthy, productive future, a downward cycle that starts right here on our sand.