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

California Thrasher In Northern Pacific Rainforest

All regionsNorthern Pacific RainforestGeneralists

California Thrasher in Northern Pacific Rainforest has collapsed: down 90% on the route-weighted index since 1971.

-90%Since 1971TrendPercent 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 →
9Routes 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 →
45YearsYears 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 →

California Thrasher has collapsed in Northern Pacific Rainforest: down 90% on the route-weighted index since 1971.

California Thrasher In Northern Pacific Rainforest Population Forecast

If the recent trend holds, California Thrasher in Northern Pacific Rainforest is projected to stay roughly flat through 2028, near 0.00 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±461.8%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.00Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1295% 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 →
±461.8%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, California Thrasher in Northern Pacific Rainforest is projected to stay roughly flat through 2028, near 0.00 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±461.8%, with 100% of held-out values landing inside the 95% band.19692028
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 →
20240.000.000.12
20250.000.000.12
20260.000.000.12
20270.000.000.12
20280.000.000.12

Routes In Northern Pacific Rainforest

Routes recording California Thrasher 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 →
Fish RockCALIFORNIA42007
HullvilleCALIFORNIA22019
French GulchCALIFORNIA22005
Shasta LakeCALIFORNIA11988
NavarroCALIFORNIA11974
LongvaleCALIFORNIA12023
Mt ShastaCALIFORNIA12013
LaytonvilleCALIFORNIA11982
Burnt RanchCALIFORNIA12013

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