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Species · Washington · BBS 2025 Release · 1966–2024

Violet-green Swallow Population Trend in Washington

All statesAerial insectivores

Violet-green Swallow in Washington has edged down: down 16% on the route-weighted index since 1970.

-16%Since 1970TrendPercent 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 →
102Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Violet-green Swallow 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 →

No notable trend signals for Violet-green Swallow in Washington. See the full index history below.

Violet-green Swallow Population Forecast in Washington

If the recent trend holds, Violet-green Swallow in Washington is projected to stay roughly flat through 2029, near 12 (95% range 6.9–16). A 5-year backtest shows a typical error of ±6.4%, with 100% of held-out values landing inside the 95% band.

+0%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 →
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 →
6.9–1695% 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 →
±6.4%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, Violet-green Swallow in Washington is projected to stay roughly flat through 2029, near 12 (95% range 6.9–16). A 5-year backtest shows a typical error of ±6.4%, with 100% of held-out values landing inside the 95% band.19682029
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 →
2025127.016
2026127.016
2027127.016
2028126.916
2029126.916

Violet-green Swallow Survey Routes in Washington

Routes recording Violet-green Swallow 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 →
Twisp9920241969
Port Angeles7920241970
South Elma5120241975
Pe Ell4720231993
Cusick4020241987
Leavenworth3720241981
Curlew3420131992
Newhalem3320241968
Raymond3120211993
Everett2720241975
Taholah2520221969
Yakima2120241993
Mukilteo2020241993
Selah2020192002
Reardan1920241968
Camas1820181971
Carnation1820241988
Mendota 31820242005
Issaquah1719871969
Snowden1720241971
Raymond 21720242022
Warm Beach1620171968
Bunker Hill1620241968
Ellensburg1620241984
Mt Rainier1620211990

Violet-green Swallow Population Trend in Other States

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