Semipalmated Sandpiper

The Semipalmated Sandpiper (Calidris pusilla) is a small, mousy-colored Sandpiper that prominently habituates arctic and sub-arctic regions near water bodies. As the name, Semipalmated suggests, their feet are partly webbed. This species of Sandpiper is particularly difficult to identify owing to its physical similarities with other Sandpipers and small birds.

About Semipalmated Sandpipers

These birds were considered to be sisters with Western Sandpipers, and these two species were formerly classified as having their own genus (Freunetes) for over 70 years. This genus was later merged into the Calidris genus. Semipalmated and Western Sandpipers maintain unique similarities to the present day and are often mistaken for one another.

They are abundantly found in the Arctic and the coasts of South America and are of low concern to conservationists. However, they are highly vulnerable to the geography of their stopover areas during migration. It is suspected that their decline of 5 % per annum in recent years is due to this vulnerability, and to offset this, special reserves have been established. This decline is believed to be due to mortality and lower population growth rates, and not a result of shifting population. As will be discussed later in this essay, efforts to conserve shorebirds will aid their population
in recovering from this decline.

The oldest recorded Semipalmated Sandpiper was found in the Canadian province of New Brunswick and is estimated to have been 14 years and 2 months old when it was captured and rereleased. Semipalmated Sandpipers are of immense allure to ornithologists and casual appreciators of nature alike. In this article, we will take a deep dive into their world.

● Semipalmated Sandpipers Photos, Color Pattern, Song
● Semipalmated Sandpipers Size, Eating behavior, Habitat
● Semipalmated Sandpipers Range and Migration, Nesting

GET KIDS BIRD WATCHING

Semipalmated Sandpiper Color Pattern

Breeding Semipalmated Sandpipers are usually brown, black, golden, and rufous on their upper parts, and have pale underparts. Their legs are a dark-color. Their heads, breasts, and napes have brown streaks, and their flanks are white. Nonbreeding adults, in contrast, lack the same flourishes. They are plainer-looking, with mousy or grey-brown upperparts, pale underparts, and weak supercilium (the lines arching over their eyes).

Juvenile Semipalmated Sandpipers have a similar color pattern to nonbreeding adults, but display a tight, scale-type pattern on their upper parts.

Description and Identification

These Sandpipers are short, with blunt-tipped bills and black legs. Their upper parts are mousy grey-brown. Their upper parts have light-colored fringes, creating a scaly pattern.

Being one of many small North American shorebirds, Semipalmated Sandpipers are a tricky species to identify correctly. They closely resemble their brethren in the Sandpiper family, as well as peeps (Calidris). Western Sandpipers have several similar features to the Semipalmated, making these two species the hardest to distinguish from each other the commonalities of black legs and small webs confuse many.

The key features to examine while identifying a Sandpiper, therefore, are the body shape, head size, and the shape of the bill. Western Sandpipers are larger and more rotund, have larger heads, and longer bills with slightly decurved tips. Semipalmated Sandpipers are a dull-hue on their upper body, and their streaks underneath are lighter in intensity.

Semipalmated Sandpipers also have an even cover of grey-brown tones above with pale fringes, creating a scaly façade. Compared to Least Sandpipers, they are larger in size. Their legs are also darker than Least Sandpipers.

Semipalmated Sandpiper Song

During the non-breeding season, these Sandpipers emit flight calls resembling “cherk”, “cher” or “che” sounds as conversational twittering, particularly in foraging groups. They make the “chert” sound in anticipation of attacks by raptors.

Vocalizations and display fights occur during the breeding season between males, and stop once the male Sandpipers find their pairs. The display fights serve the purpose of establishing territory and usually peter out once the females arrive. A motorboat resembles the sounds that males make during these fights.

Both sexes emit calls during copulation, nest defense, chick defense, and while feigning injuries. The males emit specific vocalizations during aerial displays. They also make alarm trills and scolding vocalizations.

Semipalmated Sandpiper Size

Adult Sandpipers of this species are 5.1-5.9 inches long on average and have wingspans ranging from 13.8-14.6 inches. Their mean weight is 0.7-1.1 ounces or 20-32 grams. The size and mass between sexes remain fairly consistent within a local population, but females average longer bill and wing lengths. The mass of the Sandpipers varies greatly across spring, as they acquire fat deposits during migration.

Semipalmated Sandpiper Behavior

Semipalmated Sandpipers are not very socially active, especially on breeding grounds. This is despite their legacy of being colonial breeders. They are strictly monogamous and extremely territorial and can raise a maximum of four youngins in a few weeks of arctic summer.

While feeding, these Sandpipers forage in wet mud, often digging their bills into the ground. They walk or run in between pecking and prodding. Presumably, to aid digestion, birds sleep after feeding bouts during the breeding season. It is easy to sight them while they roost during non-feeding periods.

Swimming is rare among them, and they seldom forage in water bodies. Under threat; however, older birds readily swim across the water if being pursued, especially if they have lost their flying abilities.

Semipalmated Sandpiper Diet

This species of Sandpipers subsists on a diet mainly consisting of invertebrates. They forage for Benthic invertebrates- small arthropods, amphipods, mollusks, polychaetes, and annelids in fresh or saltwater habitats. They also forage for terrestrial invertebrates, such as insects and spiders. In the Bay of Fundy, they eat the biofilm on the surface of intertidal mudflats.

Depending on the climate and humidity of the habitat, these Sandpipers also eat fly larvae, crustaceans and select seeds. During migration especially, they feed on a variety of crustaceans that they can forage for in shallow water or wet mud.

Semipalmated Sandpiper Habitat

Semipalmated Sandpipers tend to habituate low and sub-arctic tundra, in the proximity of water bodies. They nest in river deltas in dry, shrubby areas of mixed varieties of sedges and grasses, as well as barren-ground willow (Salix brachycarpa) and dwarf birch (Betula glandulosa). These Sandpipers tend to stay near the upland tundra with sparse vegetation, near small ponds, lakes, and streams. They also habituate sandy areas along rivers and sand dunes that encompass ponds.

The birds create their settlements atop small islands and hills. Their nests are under small willow bushes, or along the edges or coasts of islands in large tufts of grass.

Prior to migration, the birds flock in preparation or stage in shallow areas of either freshwater or saltwater and sparse vegetation, muddy areas, or along the edges of lakes and ponds. A crucial factor for staging habitats is that they have soft silt or clay mudflats.

Mid-migration temporary habitats include depressional wetlands in the prairie pothole region where they can forage for a variety of invertebrates, larvae, and crustaceans.

Range and Migration

Semipalmated Sandpipers maintain long ranges between their breeding and wintering stations, spanning from low arctic North America (breeding) to northern South America (wintering).

Western breeding birds migrate southwards, across the prairies with other birds from the central arctic. Most central arctic and eastern breeding birds migrate back to South America along the North Atlantic coast of North America.

There are records of southward movement between James Bay and the Guianas. Staging is common in the Bay of Fundy, which lies between the Canadian provinces of Nova Scotia and New Brunswick. From this point, most birds fly directly over the ocean, powered by excess fat reserves.

Adult birds migrate before juveniles in the fall, and so we observe two migration peaks between the age classes. Adults begin their southward journey in mid-July, peaking in late July to mid-August, and juveniles begin in mid-July to late October, reaching maxima in late August-early September.

Females usually begin migration about 5 days before males, as they usually desert broods earlier. Migration is often according to the availability of prey in staging areas when there is scarcity, the birds leave earlier. Segregation in wintering sites occurs between adult males and females.

Semipalmated Sandpiper Lifecycle

They lay the first eggs 4-6 days following pair formation. The timing of egg-laying is also heavily dependent on the availability of invertebrates for feeding. In one cycle, a female can lay up to four eggs that fit snugly in the nest cup. The intervals between laying are 30 hours long. These intervals are longer among the northerly breeding population.

After laying, females often face a deficit of calcium, and decalcified spots appear in their skulls. Males follow the leads of their partners after they lay the eggs, accompanying them from the feeding spots to nests, save for the occasional incubation spells and territorial displays.

Males and females share incubation duties equally, with males incubating during the day, and females during the night. Incubation sessions start with durations of 3-5 hours and gradually increase to up to 13-14 hours. The chicks hatch in about 19 days and begin to hunt for insects shortly. They take approximately 19 more days to fledge completely. If one of the adults is killed by a predator, the other parent deserts the nest within 5 days.

Nesting

The nesting process of Adult Semipalmated Sandpipers is rather interesting. The male birds often scrape the ground during the playing stage. This process includes the male pressing his breast against the ground and then rotating his body. The female then examines the scrapes and lines one with blades of grass, leaves, or twigs. She then sits in the nest cup and throws a lining material over the back. This is a sideways building display. Copulation in pairing occurs after nest selection, and the female adds lining to build the nest throughout the duration of laying.

The diameter of their nests ranges between 1.9-2.3 inches, and their depth ranges from 1.6-1.9 inches. The nest itself is only a depression in the mud, lined with willow birch. They often reuse the nest cups for subsequent years if hatching is successful.

Anatomy of a Semipalmated Sandpiper

Semipalmated Sandpipers are small, rotund birds with proportionally medium-sized, blunt bills. They have short legs and slight webbing between their toes. Their wings have moderate pointing. Their tails are round with slight elongation on their central rectrices.

Semipalmated Sandpiper’s average bill lengths are 0.067-0.078 inches for males and 0.071-0.087 inches for females. Females have larger bill and wing lengths than males in each population.

Final Thoughts

Semipalmated Sandpipers are indeed highly fascinating birds to study, and there are interesting points of study pertaining to them that remain under-researched. Considering their declining rate of breeding, it is important for us to focus on the study of their migration, staging, and wintering so as to optimize their habitats for better feeding and breeding.

Until the early 1900s, these birds were popularly eaten, as they could be hunted in large numbers with ease. Until protection laws came into effect for migratory birds, their numbers rapidly declined. These Sandpipers are hunted even today, both legally and illegally.

Conservation efforts are currently not being made for these birds in particular, but efforts to conserve shorebirds, in general, will help them from becoming endangered. These efforts have four main focuses: to preserve and maintain the diversity and abundance of shorebirds and heighten the quality of essential permanent and temporary habitats of shorebirds. They also ensure the availability of information on shorebirds to all regional stakeholders and decision-making and the coordination of international shorebird conservation efforts.

There is also scope for more research on the causes for sudden deaths of Semipalmated Sandpipers. These birds are especially prone to death due to botulism caused by the Clostridium botulinum bacteria, which must be studied further to examine interlinkages between anthropocentric development and botulism. Despite being on the slight decline, their population is stable for now. This is excellent news for ornithologists and keen birdwatchers, as they are likely to be sighted in sub-arctic regions.

Ornithology

Bird Watching Academy & Camp Subscription Boxes

At the Bird Watching Academy & Camp we help kids, youth, and adults get excited and involved in bird watching. We have several monthly subscription boxes that you can subscribe to. Our monthly subscription boxes help kids, youth, and adults learn about birds, bird watching, and bird conservation.

Bird Watching Binoculars for Identifying Semipalmated Sandpipers

The most common types of bird watching binoculars for viewing Semipalmated Sandpipers are 8×21 binoculars and 10×42 binoculars. Bird Watching Academy & Camp sells really nice 8×21 binoculars and 10×42 binoculars. You can view and purchase them here.

Semipalmated Sandpiper Stickers

Stickers are a great way for you to display your love for bird watching and the Semipalmated Sandpiper. We sell a monthly subscription sticker pack. The sticker packs have 12 bird stickers. These sticker packs will help your kids learn new birds every month.

Bird Feeders ForSemipalmated Sandpipers

There are many types of bird feeders. Bird feeders are a great addition to your backyard. Bird feeders will increase the chances of attracting birds drastically. Both kids and adults will have a great time watching birds eat at these bird feeders. There are a wide variety of bird feeders on the market and it is important to find the best fit for you and your backyard.

Bird Houses ForSemipalmated Sandpipers

There are many types of bird houses. Building a bird house is always fun but can be frustrating. Getting a bird house for kids to watch birds grow is always fun. If you spend a little extra money on bird houses, it will be well worth every penny and they’ll look great.