The spotted sandpiper (Actitis macularius) is a small shorebird that breeds across most of Canada and the United States. It is a migratory bird that winters from the southern United States to South America. The spotted sandpiper is known for its distinctive spotted breeding plumage and teetering motion when it walks. This species exhibits some interesting traits and behaviors.
Physical Traits
The spotted sandpiper is a small-to-medium sized shorebird, measuring around 6.7-8.3 inches in length with a wingspan of around 12-15 inches. Some key physical traits include:
Size and Shape
– Relatively small, slender shorebird
– Long legs
– Long neck and bill
– Rounded head
– Short tail
Plumage
– Non-breeding plumage: Grayish-brown upperparts, white underparts with brown streaks on breast
– Breeding plumage: Bold black spots on the white underparts and brown back
– Juvenile plumage: Upperparts brown with buff streaks, underparts white with heavy brown streaks
Bill and Legs
– Black bill that is slightly curved downward
– Yellow to orange legs
– Partial webbing between toes
Gender Differences
– Females are larger and heavier than males
– Females have browner upperparts while males are more gray
– Females have heavier spotting on the underparts
Unique Behaviors
The spotted sandpiper exhibits some interesting and unique behaviors.
Teetering Motion
– Constantly pumps its tail up and down, teetering back and forth
– This distinctive motion is used to flush out insects and larvae from mud and sand
Flight Style
– Direct, stiff flight with rapid wing beats
– Alternates bursts of wing beats with short glides
Foraging Style
– Feeds along muddy shorelines and sandbars
– Uses bill to probe into mud to catch worms, insects and other prey
– Also snatches insects from vegetation
Aggressive Displays
– Highly aggressive toward intruders in its breeding territory
– Will spread wings and tail, raise head, and run directly at intruder
Mating Displays
– Male performs “broken wing” display, dragging one wing on ground to lure potential predators away from nest
– Both sexes participate in “butterfly flight”display, slowly fluttering over breeding territory
Breeding and Nesting
The spotted sandpiper has some unique breeding behaviors.
Polyandry
– Females are polyandrous, breeding with more than one male per season
– Each male incubates the eggs and cares for chicks separately
Solitary Nesters
– Nest in solitude, unlike many shorebirds that nest in colonies
– Both parents share incubation duties
Nest Sites
– Scrape out a shallow depression on the ground lined with grasses and leaves
– Common nest sites include fields, gravel bars, sandy beaches
Clutch Size
– Lay between 3-5 eggs per clutch
– Cream or buff-colored eggs with brown spotting
Chick Rearing
– Precocial young, able to feed themselves soon after hatching
– Chicks will leave the nest within hours after hatching
– Males assume most of the brood rearing duties
Migration
The spotted sandpiper is a long-distance migrant, wintering south of its breeding range.
Migration Timing
– Leave wintering grounds in April and May
– Begin arriving on breeding grounds in May and June
– Southward migration starts in July, peaks in August
– Most arrive on wintering grounds by October
Migration Route
– Follow interior flyways across North America
– Make nonstop flights across Gulf of Mexico and Caribbean
Winter Range
– Winters in southern U.S. south through Mexico, Central America, and northern South America
– Found around mudflats, lakeshores, flooded fields
Long-Distance Migrants
– Migrate from breeding range that spans across northern North America
– Travel over 2,400 miles between breeding and wintering grounds
Habitat and Range
The spotted sandpiper occupies a broad range of freshwater and coastal habitats during the breeding season.
Breeding Habitat
– Found near water across a variety of wetland habitats
– Lakeshores, river edges, mudflats, flooded fields
Nesting Habitat
– Nests in open fields, gravel bars, beaches and shorelines
– Usually nests close to foraging areas near water
Winter Habitat
– Coastal mudflats, beaches, flooded agricultural fields
– Also found along lakes, rivers, and streams
Range
| Season | Range |
|---|---|
| Breeding | Throughout Alaska and Canada, south throughout the continental United States |
| Migration | Throughout North America following main flyways |
| Wintering | Southern U.S. south to northern South America |
Diet
The spotted sandpiper is an opportunistic forager that feeds on a variety of animal prey.
Foraging Habits
– Walks along muddy shorelines searching for food
– Uses visual searches and probes bill into mud or sand
– Also wades into shallow water to capture prey
Prey
– Mainly insects, other invertebrates like crustaceans and mollusks
– Also small fish, tadpoles, frogs
Feeding Techniques
– Probe into mud or sand to find buried prey
– Dart out to grab insects from shoreline vegetation
– Pluck insects from water surface
– Capture tadpoles and small fish by stirring up sediment
Diet Composition
| Prey Type | Percentage of Diet |
|---|---|
| Insects | 50-90% |
| Other invertebrates | 5-40% |
| Small fish | 5-15% |
| Other vertebrates | 5-10% |
Population Status
The spotted sandpiper has an extremely large population and breeding range.
Population Size
– Extremely large population estimated between 3.5 to 4.5 million birds
– One of the most common and widespread shorebirds in North America
Population Trend
– Population considered stable with increasing trend
– Has adapted well to human-altered waterways and shorelines
Conservation Status
– Listed as species of Least Concern on IUCN Red List
– Does not qualify for protected status under endangered species laws
Threats
– Some threats from pesticides and degradation of migratory wetland habitat
– Vulnerable to oil spills in coastal wintering habitat
– Overall low level of threat compared to other shorebirds
Interesting Facts
Here are a few interesting facts about the spotted sandpiper:
– Polyandrous mating system is unique among shorebirds
– One of the only shorebirds that is equally common in interior regions
– Males perform all incubation and majority of brood rearing duties
– One of the earliest spring migrant shorebirds, returning in April and May
– Aggressive displays include wing-spreading and bill-pointing at intruders
– Has very large range, breeding across nearly all of North America
Conclusion
In summary, the spotted sandpiper is a widespread North American shorebird known for its teetering movements, boldly-spotted breeding plumage, polyandrous mating habits, and aggression toward intruders. It breeds across a variety of freshwater wetlands and coastal habitats. Other notable traits include a distinctly curved bill, partial webbing between the toes, and a direct flight style. It is a long-distance migrant that travels between breeding grounds and wintering areas in the southern U.S. and beyond. With a large population and few major threats, the spotted sandpiper remains one of the most common and adaptable shorebirds in North America.
