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

Northern Harrier In Northern Pacific Rainforest

All regionsNorthern Pacific RainforestGeneralists

Northern Harrier in Northern Pacific Rainforest has surged: up 94% on the route-weighted index since 1973.

+94%Since 1973TrendPercent 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 →
43Routes 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 →
51YearsYears 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 increasecomputed 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 →

Northern Harrier has surged in Northern Pacific Rainforest: up 94% on the route-weighted index since 1973.

Northern Harrier In Northern Pacific Rainforest Population Forecast

If the recent trend holds, Northern Harrier in Northern Pacific Rainforest is projected to fall about 14% by 2029 — from 0.16 in 2024 to a central estimate of 0.14 (95% range 0.06–0.22). A 5-year backtest shows a typical error of ±125.2%, with 80% of held-out values landing inside the 95% band.

-14%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 →
0.14Projected 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 →
0.06–0.2295% 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 →
±125.2%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 Harrier in Northern Pacific Rainforest is projected to fall about 14% by 2029 — from 0.16 in 2024 to a central estimate of 0.14 (95% range 0.06–0.22). A 5-year backtest shows a typical error of ±125.2%, 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 →
20250.130.050.21
20260.130.050.21
20270.130.060.21
20280.140.060.21
20290.140.060.22

Routes In Northern Pacific Rainforest

Routes recording Northern Harrier 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 →
YrekaCALIFORNIA52019
McminnvilleOREGON42024
AdairOREGON32024
CordovaALASKA22009
Mitkof IsleALASKA22002
Bodega BayCALIFORNIA22021
CanbyOREGON22017
SalemOREGON22024
Bay ViewWASHINGTON22017
Mendota 2WASHINGTON21994
Thompson PasALASKA12023
Sheep MtnALASKA12014
Copper RiverALASKA12009
Crescent CtyCALIFORNIA11979
HoneydewCALIFORNIA12005
Martins FyCALIFORNIA11977
Rio DellCALIFORNIA11996
Mt ShastaCALIFORNIA11995
GazelleCALIFORNIA11991
UmpquaOREGON12018
WinberryOREGON12023
ScioOREGON12024
DaytonOREGON12015
GarfieldOREGON12013
ElktonOREGON12024

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