BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Wilson's Phalarope Population Analysis

ScolopacidaeShorebirdsPhalaropus tricolor

Wilson's Phalarope has surged: up 120% on the route-weighted index since 1968.

+120%Since 1968TrendPercent 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 →
481RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
59Years 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 Wilson's Phalarope

The Wilson's Phalarope (Phalaropus tricolor) 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 481 Breeding Bird Survey routes across 20 states, most concentrated in the Great Basin.
Family
Scolopacidae · Shorebirds

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

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Wilson's Phalarope has surged in surveyed states: up 120% on the route-weighted index since 1968.

Wilson's Phalarope Population Forecast

If the recent trend holds, Wilson's Phalarope is projected to rise about 12% by 2030 — from 0.19 in 2025 to a central estimate of 0.21 (95% range 0.10–0.32). A 5-year backtest shows a typical error of ±56.9%, with 80% of held-out values landing inside the 95% band.

+12%Change by 2030TrendPercent 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 →
0.21Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.10–0.3295% 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 →
±56.9%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, Wilson's Phalarope is projected to rise about 12% by 2030 — from 0.19 in 2025 to a central estimate of 0.21 (95% range 0.10–0.32). A 5-year backtest shows a typical error of ±56.9%, with 80% of held-out values landing inside the 95% band.19662030
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 →
20260.210.100.31
20270.210.100.31
20280.210.100.32
20290.210.100.32
20300.210.100.32

Where the Wilson's Phalarope Is Detected

BBS routes recording Wilson's Phalarope, sized by most recent count.

Wilson's Phalarope Population Trend by State

Wilson's Phalarope 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 →
California-8%197322
Colorado-76%197343
Idaho-79%197430
Illinoisinsufficient datan/a1
Iowainsufficient datan/a1
Kansas-51%19736
Minnesota-77%19789
Montana+29%197068
Nebraska+53%197324
Nevada+416%197316
New Mexicoinsufficient datan/a4
North Dakota+23%196949
Oklahomainsufficient datan/a3
Oregon-78%197141
South Dakota-57%196946
Texas+18%19896
Utah-78%198519
Washington-73%197914
Wisconsininsufficient datan/a6
Wyoming+145%197173

Wilson's Phalarope Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Wilson's Phalarope 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 →
Northern Pacific Rainforest-80%19773
Great Basin-6%1971104
Northern Rockies+116%197085
Prairie Potholes+15%196986
Sierra Nevada-52%19763
Southern Rockies / Colorado Plateau-76%197032
Badlands and Prairies-3%196996
Shortgrass Prairie+279%198240
Central Mixed Grass Prairie+101%196917

Wilson's Phalarope Conservation Status

Our route-weighted index shows it up about 120% since 1968. Many shorebirds have declined steeply, reflecting pressure on the coastal and wetland stopovers they depend on.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.