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

Common Loon In BCR 4

All regionsBCR 4Wetland birds

Common Loon in BCR 4 has declined: down 49% on the route-weighted index since 1983.

-49%Since 1983TrendPercent 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 →
41Routes 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 →
43YearsYears 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 Common Loon in BCR 4. See the full index history below.

Common Loon In BCR 4 Population Forecast

If the recent trend holds, Common Loon in BCR 4 is projected to fall about 67% by 2029 — from 0.50 in 2024 to a central estimate of 0.17 (95% range 0.00–0.90). A 5-year backtest shows a typical error of ±77.8%, with 100% of held-out values landing inside the 95% band.

-67%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 →
0.17Projected 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 →
0.00–0.9095% 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 →
±77.8%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, Common Loon in BCR 4 is projected to fall about 67% by 2029 — from 0.50 in 2024 to a central estimate of 0.17 (95% range 0.00–0.90). A 5-year backtest shows a typical error of ±77.8%, with 100% of held-out values landing inside the 95% band.19782029
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 →
20250.240.000.98
20260.220.000.96
20270.200.000.94
20280.180.000.92
20290.170.000.90

Routes In BCR 4

Routes recording Common Loon 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 →
WillowALASKA72024
Skilak LakeALASKA41985
McgrathALASKA42022
TonsinaALASKA32018
Lake LouiseALASKA32011
Burma RoadALASKA32023
KuskulanaALASKA32024
Chena Hot SpALASKA21986
Swan Lake RdALASKA22023
WasillaALASKA21983
Moose CreekALASKA22016
Porcupine R.ALASKA22002
Ft. RichrdsnALASKA22023
Kanuti LakeALASKA22023
Galena (Short)ALASKA22022
Paxson LakeALASKA21997
Nabesna RoadALASKA22024
Mccarthy Rd2ALASKA22024
CircleALASKA12017
Birch LakeALASKA11993
SlanaALASKA12024
ChistochinaALASKA12008
MaclarenALASKA12016
MonahanALASKA12017
CantwellALASKA12013

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