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Species · Washington · BBS 2025 Release · 1966–2024

Northern Rough-winged Swallow Population Trend in Washington

All statesAerial insectivores

Northern Rough-winged Swallow in Washington has held roughly steady: down 9% on the route-weighted index since 1970.

-9%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 →
103Routes 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 Northern Rough-winged 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 Northern Rough-winged Swallow in Washington. See the full index history below.

Northern Rough-winged Swallow Population Forecast in Washington

If the recent trend holds, Northern Rough-winged Swallow in Washington is projected to fall about 22% by 2029 — from 3.4 in 2024 to a central estimate of 2.6 (95% range 0.33–4.9). A 5-year backtest shows a typical error of ±48%, with 100% of held-out values landing inside the 95% band.

-22%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 →
2.6Projected 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 →
0.33–4.995% 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 →
±48%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, Northern Rough-winged Swallow in Washington is projected to fall about 22% by 2029 — from 3.4 in 2024 to a central estimate of 2.6 (95% range 0.33–4.9). A 5-year backtest shows a typical error of ±48%, 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 →
20252.60.364.9
20262.60.354.9
20272.60.344.9
20282.60.344.9
20292.60.334.9

Northern Rough-winged Swallow Survey Routes in Washington

Routes recording Northern Rough-winged 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 →
Malden6220241999
Ewan 25220242023
Harwood4719971993
Walla Walla3019931993
Hartline2820061994
Laurier2220222004
Hanford Site2019961991
Selah1920142000
Mesa1820081994
Pomona1819991999
Yakima1420231993
Pomeroy1220242005
Horn Rapids1220152005
Twisp1120241969
Ewan1120191985
Cougar820231969
Potholes820231996
Prescott720191981
Lake Chelan720241988
Ozette620241971
Wilbur620171985
Nighthawk620241992
Newhalem520241968
South Elma520241984
Port Angeles420241973

Northern Rough-winged Swallow Population Trend in Other States

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

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