BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Semipalmated Sandpiper

ScolopacidaeShorebirdsCalidris pusilla

Semipalmated Sandpiper has surged: up 376% on the route-weighted index since 1994.

+376%Since 1994TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
12RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
32Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Semipalmated Sandpiper

The Semipalmated Sandpiper (Calidris pusilla) is a North American member of the Sandpipers & Allies (Scolopacidae). In this analysis it is grouped with the shorebirds.

Size
5–26 in long (13–66 cm) — a probing shorebird (typical for the family)
Habitat
Shorelines, mudflats, beaches, flooded fields and wet meadows.
Diet
Invertebrates probed or picked from mud, sand and shallow water.
Range
Recorded on 12 Breeding Bird Survey routes across 1 state, most concentrated in the BCR 2.
Family
Scolopacidae · Shorebirds

Notable Semipalmated Sandpiper TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Semipalmated Sandpiper. See the full index history below.

Semipalmated Sandpiper Population Forecast

If the recent trend holds, Semipalmated Sandpiper is projected to stay roughly flat through 2029, near 0.04 (95% range 0.01–0.06). A 5-year backtest shows a typical error of ±42.7%, with 80% of held-out values landing inside the 95% band.

n/aChange by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.04Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.01–0.0695% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±42.7%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Semipalmated Sandpiper is projected to stay roughly flat through 2029, near 0.04 (95% range 0.01–0.06). A 5-year backtest shows a typical error of ±42.7%, with 80% of held-out values landing inside the 95% band.19862029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.030.010.06
20260.030.010.06
20270.030.010.06
20280.040.010.06
20290.040.010.06

Where the Semipalmated Sandpiper Is Detected

BBS routes recording Semipalmated Sandpiper, sized by most recent count.

Semipalmated Sandpiper Population Trend by State

Semipalmated Sandpiper population trend by state.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alaska+291%199412

Semipalmated Sandpiper Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Semipalmated Sandpiper population trend by Bird Conservation Region.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
BCR 2+183%19947

Semipalmated Sandpiper Conservation Status

Our route-weighted index shows it up about 376% since 1994. Many shorebirds have declined steeply, reflecting pressure on the coastal and wetland stopovers they depend on.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.