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

Merlin In BCR 4

All regionsBCR 4Generalists

Merlin in BCR 4 has edged up: up 23% on the route-weighted index since 1988.

+23%Since 1988TrendPercent 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 →
35Routes 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 →
36YearsYears 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 →

No notable trend signals for Merlin in BCR 4. See the full index history below.

Merlin In BCR 4 Population Forecast

If the recent trend holds, Merlin in BCR 4 is projected to rise about 72% by 2029 — from 0.08 in 2024 to a central estimate of 0.14 (95% range 0.03–0.26). A 5-year backtest shows a typical error of ±58%, with 100% of held-out values landing inside the 95% band.

+72%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 →
0.03–0.2695% 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 →
±58%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, Merlin in BCR 4 is projected to rise about 72% by 2029 — from 0.08 in 2024 to a central estimate of 0.14 (95% range 0.03–0.26). A 5-year backtest shows a typical error of ±58%, with 100% of held-out values landing inside the 95% band.19862029
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 →
20250.140.030.25
20260.140.030.25
20270.140.030.25
20280.140.030.25
20290.140.030.26

Routes In BCR 4

Routes recording Merlin 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 →
ToklatALASKA42021
KalifonskyALASKA42018
Ft. RichrdsnALASKA32008
TatalinaALASKA32012
ChistochinaALASKA22023
MaclarenALASKA22001
CohoeALASKA22023
Caribou Mtn.ALASKA22022
Moose CreekALASKA22010
KuskulanaALASKA22024
EagleALASKA12023
Chatanika RALASKA12021
Birch LakeALASKA12007
LivengoodALASKA12010
SlanaALASKA12014
MonahanALASKA12018
CantwellALASKA12021
L SalchaALASKA11988
Chena Hot SpALASKA11990
Kenny LakeALASKA12017
ChickenALASKA11994
SavageALASKA12021
Hatcher PassALASKA12015
Swan Lake RdALASKA12004
Anchor RiverALASKA12018

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