BirdAnalyst
Species · Washington · BBS 2025 Release · 1966–2024

Purple Martin Population Trend in Washington

All statesAerial insectivores

Purple Martin in Washington has risen sharply: up 74% on the route-weighted index since 1982.

+74%Since 1982TrendPercent 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 →
14Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
29YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Purple Martin Trends in WashingtonNotable 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 →

Purple Martin has risen sharply in Washington: up 74% on the route-weighted index since 1982.

Purple Martin Population Forecast in Washington

If the recent trend holds, Purple Martin in Washington is projected to fall about 42% by 2029 — from 0.32 in 2024 to a central estimate of 0.18 (95% range 0.00–0.41). A 5-year backtest shows a typical error of ±51.8%, with 60% of held-out values landing inside the 95% band.

-42%Change 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 →
0.18Projected 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 →
0.00–0.4195% 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 →
±51.8%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, Purple Martin in Washington is projected to fall about 42% by 2029 — from 0.32 in 2024 to a central estimate of 0.18 (95% range 0.00–0.41). A 5-year backtest shows a typical error of ±51.8%, with 60% of held-out values landing inside the 95% band.19712029
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 →
20250.170.000.40
20260.170.000.40
20270.180.000.40
20280.180.000.41
20290.180.000.41

Purple Martin Survey Routes in Washington

Routes recording Purple Martin in Washington.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Bunker Hill1520241974
Vashon Is.520212006
Mendota 3320242005
Everett219871987
South Elma220232023
Kamilche220062006
Issaquah219711971
Pe Ell220232019
Cougar220192019
Port Angeles120212011
Packwood120122012
Rainier120192019
Mcchord120151996
Snowden119821982

Purple Martin Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.