Western Sandpiper––a beautiful shorebird, soon-to-be film star

Western sandpipers are the most common shorebird on the Seward Peninsula and one of the most abundant shorebirds in the western hemisphere.

Perhaps because they are so common, these little waders are sometimes under-appreciated. Western sandpipers are such beautiful birds when they pause in their busy lives long enough to be admired. And during migration, when hundreds or thousands of individuals form shimmering, shape-shifting flocks that turn and swirl in perfect synchrony, they cannot fail to impress.

Most shorebirds, including western sandpipers, are long-distance migrants that travel vast distances twice a year between northern breeding grounds and wintering areas far to the south.

This traveling lifestyle has become increasingly risky in our rapidly changing world. Natural habitats are disappearing quickly. Many traditional stopover sites that birds rely upon for food and rest on their journey are being altered for human purposes without consideration for the wildlife that depends on them. As a result, shorebirds are one of the most rapidly declining groups of birds.

Huge, dazzling flocks of western sandpipers travel to and from their wintering areas along the Pacific coast from British Colombia to Peru. En route, flocks pause at a handful of important stopover sites to rest and refuel. Tens of thousands of voracious sandpipers may be seen at a time feeding at these food-rich sites.

One such critical site is Roberts Bank, a mud flat in the Fraser River delta in British Columbia. Between 42 and 65 percent of the global western sandpiper population is estimated to refuel at Roberts Bank in a given year and the entire population is believed to feed there at some point in their lives.

Roberts Bank is a uniquely energizing refueling stop for sandpipers. There, the intertidal mud flats are coated with a biofilm that is rich in omega-3 fatty acids. It is produced by diatoms, a type of single-celled algae. Western sandpipers, dunlin and semipalmated sandpipers have specialized, bristly tongues for collecting this energy-packed slurry that fuels their migration.

Tragically, Roberts Bank is threatened by an expansion of the Port of Vancouver. If the expansion occurs as proposed, this critical stopover for millions of migratory shorebirds will be lost.

To raise awareness of the issue, Canadian filmmaker Isabelle Groc is producing a documentary about shorebird conservation, and western sandpipers in particular.

In June, Groc and her film crew came to Nome to film western sandpipers on a breeding ground. Western sandpipers breed across the Seward Peninsula in upland and lowland habitats with a mix of dwarf shrubs and meadows. For the filming, an easily accessible site at the west end of Safety Sound was chosen, where western sandpipers have been studied periodically since the 1980s.

Jim Johnson, a biologist with the U.S. Fish and Wildlife Service, Nick Hajdukovich, a former bird biologist, now pilot, and I were asked to help Groc locate western sandpipers and their nests, broods and breeding behaviors.

Typically, western sandpipers arrive in mid to late May depending on conditions. Harsh weather, lack of food and predation often greet them when they reach their breeding ground. This year’s late spring was especially unwelcoming. At the study area, many arriving sandpipers found a solid cover of snow and ice, which delayed nesting.

Males arrive first to establish and defend their territories, often returning to the same territory each year. They defend their boundaries with aerial displays and buzzy, trilling songs.

Females arrive a few days later and monogamous pair bonds form, sometimes with the previous mate. The male makes multiple nest depressions amongst dried grass and leads his prospective mate to inspect them. She picks one for their nest site and together they improve it. Up to four eggs are laid. The pair shares incubation, periodically rotating the eggs.

When Groc and her film crew arrived in early June, they filmed courtship, territorial displays and disputes, but incubation and egg laying that normally would be in full swing was only just beginning when they left.

Finally, on the last day of filming, we found a few incubating birds on nests. This allowed Groc to document egg collection for a research project that involved taking a single, newly-laid egg from three nests in the Nome area. The eggs will be analyzed for the fatty acid signature of the Roberts Bank biofilm. If found, it will indicate that the biofilm fuels reproduction as well as migration, thus increasing the importance of protecting migratory sites where the biofilm occurs.

In most years, egg laying is quite synchronous. Western sandpiper eggs hatch in 21 days, and hatch peeks around June 22 to 26. But this late spring resulted in an unusual breeding season.

When Groc returned in late June to film chicks on the tundra, most eggs were still unhatched. The few chicks that we found were at various stages of development, from newly hatched to a chick that could fly.

At hatch, chicks are covered in richly patterned down that hides them from predators (and biologists) in the tundra vegetation. Within 24 hours the long-legged chicks are ready to leave the nest and follow their parents, who are their guides and protectors. They warm the chicks by brooding them until they can regulate their own body temperature.

Parents lead their brood to wet areas with abundant food, warn the chicks of danger and attempt to deflect it. They draw predators away by scurrying dramatically across the tundra with fluffed feathers in a “rodent run” display, or flutter as if with a broken wing while sounding a loud distress call.

When the chicks are about seven to ten days old, the female, depleted by egg production, leaves the chicks in the care of her mate. The chicks fledge about 21 days after hatch. Then the father, too, departs to feed in preparation for migration.

On the breeding ground, western sandpipers feed mostly on insects and spiders that they pick off the surface of the tundra. In wintering areas and at migratory stopovers the sandpipers probe for marine invertebrates.

Females have longer bills than males, enabling them to probe more deeply and take larger prey. This reduces competition between the sexes. Both sexes use their brushy tongues to slurp up biofilm and organic material in intertidal waters.

By early July flocks of failed breeders and post-breeding females gather on coastal mudflats and shores. Flocks increase in size as males and juveniles move to the coast and are joined by other shorebird species.

Most western sandpiper adults leave by mid-July, while the young continue feeding in coastal areas for a few more weeks. Numbers peak in late July and early August, then drop sharply. Migrants from nesting areas further north continue passing through into September.

While western sandpipers are fewer than they once were, you can still marvel at the sight of synchronized, swooping, swirling shorebird flocks in the coming weeks. And keep an eye out for Groc’s film “Sandpipers’ Last Supper,” that should be released in the coming year.

Comment period

You can help protect critical habitat for migratory and breeding birds in the Nome area. Now is the time to submit public comments to the Department of Environmental Conservation regarding a permit authorizing IPOP to discharge water from their planned mining operation into the fragile Safety Sound estuary that supports vast numbers of birds, fish, marine mammals and subsistence activities.

For more information, to request a public hearing or to submit public comments, contact: allan.nakanishi@alaska.gov

Comments are due by August 5, 2024.