Birder’s Notebook: Semipalmated Plover––the shorebird in a tuxedo

Semipalmated plovers are plump little shorebirds sporting a black-and-white face mask and a distinctive black band across the white chest––eye catching, one would think. But it is said that this plover’s bold, tuxedo-like markings actually help disguise it in their preferred, gravel habitat by breaking up the bird’s outline.
And indeed, recently, as I walked along the edge of Salmon Lake amidst mixed flocks of small foraging shorebirds, the boldly patterned plovers were just as hard to spot against the beach gravel as were their plainly marked sandpiper companions
Semipalmated plovers breed across the Seward Peninsula in sparsely vegetated habitats where gravel or coarse sand are exposed. They are attracted to gravel ridges, gravel bars, lake shores, roads, runways and even gravel pads for nest sites. These plovers are a familiar sight along Nome area roads, which appear to offer great nesting opportunities but can be a fatal choice.
On St. Lawrence Island semipalmated plovers pass through during migration, and increasing numbers are reported to be breeding in the Gambell area.
Generally, these shorebirds are only found along coastal beaches during migration.
Spring migrants arrive in mid-May. Males come first to establish their territories, which they advertise with display flights and incessant “chu-weep” calls. Making wide circles over his territory, the male’s exaggerated wingbeats are slow, deep and floppy-looking. Males also prepare nest scrapes to lure arriving females.
When a female is attracted, the male chases her and a ground display ensues. He spreads and fans his tail, fluffs his feathers, opens his wings and calls excitedly.
Some pairs reform in subsequent years.  
Most shorebirds that breed in the north nest in the tundra, but semipalmated plovers prefer to nest on well-drained gravel, coarse sand or amid sparse vegetation. The nest is a shallow depression (scrape,) often near water or wet ground where the plovers feed. The scrape is sometimes scantily lined with small leaves.
Four eggs are usually laid, typically during the first week of June. The female lays an egg a day and incubation begins when the third or fourth egg is laid. This ensures that all eggs hatch at close to the same time.
Both sexes incubate for 23 to 25 days, and hatch generally peaks in early July.
The downy, long-legged, well-developed young are beautifully patterned for camouflage. They venture from the nest as soon as the last chick is dry. Both parents tend their young, brooding them during their first few days, and leading them to foraging areas where they find their own food.
When danger approaches, the parents sound an alarm call and the chicks immediately crouch and freeze, remaining motionless and virtually undetectable until danger passes and warning calls cease. The parents respond to human intruders by crouching and running or feigning injury. At the approach of other potential predators, the parents typically run from the nest and stand a ways away calling loudly.
The female leaves the young in the care of her mate 15 to 25 days after hatch. The male continues to tend and defend the chicks until they fledge in 23 to 31 days.
Usually, most chicks have fledged by early August.
On the breeding ground semipalmated plovers eat insects and their larvae, spiders, freshwater aquatic invertebrates and small worms. The plovers feed in moist areas, along shorelines, or along small pools formed by melting snow.
“Semipalmated” refers to the plover’s partially webbed toes, which are helpful when moving over soggy ground.
When on the coast during migration and in winter, their diet switches to marine invertebrates such as crustaceans, mollusks and marine worms.
Like all plovers, semipalmated plovers have a distinctive stop and go foraging style, running a few steps, then stopping abruptly to look for prey before another brief sprint. When prey is spotted, they tip forward at the ankle with the tail raised and the head down to quickly snatch their prey from the surface.
They also hunt in shallow water by pattering their feet to stir up sediment and flush prey that they quickly grab. Their large, well-developed eyes give them night vision to feed in the dark at times.
Adults depart on migration by the end of July or early August and few semipalmated plovers remain here after mid-August. Western populations, such as ours, winter in coastal areas of the Pacific from northern California to central Chile.
Semipalmated plovers are tolerant of people and will nest in proximity to human activity. Their nests are in the open and their eggs are very well camouflaged. So, if a distressed parent alerts you that a nest is nearby, watch where you put your feet!
These handsome and cheery little plovers are widespread and common in North America. They are one of only a few shorebird species whose population is believed to be stable.

Plover or Sandpiper?
Plovers and sandpipers are types of shorebirds that, during migration, are often seen feeding together in flocks along coastal beaches and estuaries. They can be confusing to tell apart until you know what to look for.

Plovers have stout, more rounded bodies and large rounded heads with big eyes. Their bills are short and stubby. Common plovers seen in the Bering Strait region are the semipalmated plover, the American golden-plover, the Pacific golden-plover and the black-bellied plover.

Sandpipers have longer, more slender bodies and slender bills that can be of varying lengths and strait or curved. There are many sandpipers in the region, but the most common small sandpipers include the western sandpiper, the semipalmated sandpiper and the least sandpiper.

If you watch these shorebirds feeding together in flocks, their feeding styles can help you tell them apart. Plovers have a stop and go foraging method––they rush forward and stop abruptly to look for prey, quickly snatching it from the surface or pulling worms from the gravel, followed by another short burst forward. Sandpipers run along the beach and stop to use their slender bills to probe into the gravel or sand for food.