BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Western Sandpiper

ScolopacidaeShorebirdsCalidris mauri

Western Sandpiper has risen sharply: up 74% on the route-weighted index since 1994.

+74%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 →
14RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
29Years 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 Western Sandpiper

The Western Sandpiper (Calidris mauri) 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 14 Breeding Bird Survey routes across 1 state, most concentrated in the BCR 2.
Family
Scolopacidae · Shorebirds

Notable Western 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 Western Sandpiper. See the full index history below.

Western Sandpiper Population Forecast

If the recent trend holds, Western Sandpiper is projected to stay roughly flat through 2029, near 0.12 (95% range 0.00–0.40). A 5-year backtest shows a typical error of ±281.9%, with 60% 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 →
0.12Projected 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 →
0.00–0.4095% 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 →
±281.9%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, Western Sandpiper is projected to stay roughly flat through 2029, near 0.12 (95% range 0.00–0.40). A 5-year backtest shows a typical error of ±281.9%, with 60% of held-out values landing inside the 95% band.19822029
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 →
20250.110.000.39
20260.110.000.39
20270.110.000.40
20280.120.000.40
20290.120.000.40

Where the Western Sandpiper Is Detected

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

Western Sandpiper Population Trend by State

Western 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+31%199414

Western Sandpiper Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Western 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+218%199512

Western Sandpiper Conservation Status

Our route-weighted index shows it up about 74% 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.