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Species · BCR 5 · BBS 2025 Release · 1966–2024

Heermann's Gull In Northern Pacific Rainforest

All regionsNorthern Pacific RainforestWetland birds

Heermann's Gull in Northern Pacific Rainforest has collapsed: down 86% on the route-weighted index since 1981.

-86%Since 1981TrendPercent 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 →
7Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
23YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 declinecomputed 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 →

Heermann's Gull has collapsed in Northern Pacific Rainforest: down 86% on the route-weighted index since 1981.

Heermann's Gull In Northern Pacific Rainforest Population Forecast

If the recent trend holds, Heermann's Gull in Northern Pacific Rainforest is projected to stay roughly flat through 2022, near 0.03 (95% range 0.00–0.33). A 5-year backtest shows a typical error of ±458.4%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2022TrendPercent 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 →
0.03Projected 2022 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.3395% 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 →
±458.4%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, Heermann's Gull in Northern Pacific Rainforest is projected to stay roughly flat through 2022, near 0.03 (95% range 0.00–0.33). A 5-year backtest shows a typical error of ±458.4%, with 100% of held-out values landing inside the 95% band.19692022
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 →
20180.040.000.34
20190.040.000.34
20200.040.000.34
20210.030.000.33
20220.030.000.33

Routes In Northern Pacific Rainforest

Routes recording Heermann's Gull in Northern Pacific Rainforest.
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 →
Hazel CampOREGON202001
TaholahWASHINGTON41987
Fish RockCALIFORNIA32003
HoneydewCALIFORNIA12014
Bodega BayCALIFORNIA12017
WedderburnOREGON11992
OzetteWASHINGTON11986

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