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Species · BCR 4 · BBS 2025 Release · 1966–2024

Peregrine Falcon In BCR 4

All regionsBCR 4Generalists

Peregrine Falcon in BCR 4 has surged: up 263% on the route-weighted index since 1998.

+263%Since 1998TrendPercent 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 →
16Routes 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 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 →

Peregrine Falcon has surged in BCR 4: up 263% on the route-weighted index since 1998.

Peregrine Falcon In BCR 4 Population Forecast

If the recent trend holds, Peregrine Falcon in BCR 4 is projected to rise about 66% by 2027 — from 0.07 in 2022 to a central estimate of 0.11 (95% range 0.04–0.19). A 5-year backtest shows a typical error of ±43.6%, with 80% of held-out values landing inside the 95% band.

+66%Change by 2027TrendPercent 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 →
0.11Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.04–0.1995% 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 →
±43.6%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, Peregrine Falcon in BCR 4 is projected to rise about 66% by 2027 — from 0.07 in 2022 to a central estimate of 0.11 (95% range 0.04–0.19). A 5-year backtest shows a typical error of ±43.6%, with 80% of held-out values landing inside the 95% band.19962027
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 →
20230.100.030.18
20240.110.030.18
20250.110.030.18
20260.110.040.19
20270.110.040.19

Routes In BCR 4

Routes recording Peregrine Falcon in BCR 4.
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 →
NorthwayALASKA22019
EagleALASKA12014
SlanaALASKA12005
Tower BluffsALASKA12010
MaclarenALASKA12013
MonahanALASKA11997
CantwellALASKA12017
ChickenALASKA12022
Unalakleet RiverALASKA12006
Hather CreekALASKA12015
Kanuti CanynALASKA12017
McgrathALASKA12022
Manley Ht SpALASKA12021
Porcupine R.ALASKA11998
Anvik RiverALASKA12022
Kanuti LakeALASKA12021

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