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

Common Loon Population Trend in Washington

All statesWetland birds

Common Loon in Washington has edged down: down 11% on the route-weighted index since 1977.

-11%Since 1977TrendPercent 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 →
27Routes 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 →
41YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Common Loon 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 Common Loon in Washington. See the full index history below.

Common Loon Population Forecast in Washington

If the recent trend holds, Common Loon in Washington is projected to fall about 65% by 2029 — from 0.10 in 2024 to a central estimate of 0.04 (95% range 0.00–0.11). A 5-year backtest shows a typical error of ±39.3%, with 80% of held-out values landing inside the 95% band.

-65%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 →
0.04Projected 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 →
0.00–0.1195% 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 →
±39.3%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, Common Loon in Washington is projected to fall about 65% by 2029 — from 0.10 in 2024 to a central estimate of 0.04 (95% range 0.00–0.11). A 5-year backtest shows a typical error of ±39.3%, with 80% 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 →
20250.040.000.11
20260.040.000.11
20270.040.000.11
20280.040.000.11
20290.040.000.11

Common Loon Survey Routes in Washington

Routes recording Common Loon 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 →
Raymond 2520242024
Ozette420091976
Laurier320221999
Ardenvoir219841984
Ilwaco219771977
Cedar Falls220132011
Port Angeles119711971
Warm Beach120072007
Hanford Site119921992
Brewster120141979
Keller119711971
No Cascades120071988
Cougar119901988
Rimrock120141991
Sullivan Lake 2120152005
Tonasket120182018
Twin Lakes120241983
Cusick120002000
Ronald120152015
Packwood119871987
Nighthawk120191996
Curlew120132005
Horn Rapids120212021
Raymond120071993
Bay View120151997

Common Loon Population Trend in Other States

alaskaidahomainemassachusettsmichiganminnesotamontananew-hampshirenew-yorknorth-dakotaoregonvermontwisconsinwyoming

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