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

Trumpeter Swan In BCR 4

All regionsBCR 4Waterfowl

Trumpeter Swan in BCR 4 has surged: up 133% on the route-weighted index since 1987.

+133%Since 1987TrendPercent 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 →
31Routes 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 →
38YearsYears 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 →

Trumpeter Swan has surged in BCR 4: up 133% on the route-weighted index since 1987.

Trumpeter Swan In BCR 4 Population Forecast

If the recent trend holds, Trumpeter Swan in BCR 4 is projected to rise about 63% by 2029 — from 0.78 in 2024 to a central estimate of 1.3 (95% range 0.47–2.1). A 5-year backtest shows a typical error of ±49.6%, with 80% of held-out values landing inside the 95% band.

+63%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 →
1.3Projected 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 →
0.47–2.195% 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 →
±49.6%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, Trumpeter Swan in BCR 4 is projected to rise about 63% by 2029 — from 0.78 in 2024 to a central estimate of 1.3 (95% range 0.47–2.1). A 5-year backtest shows a typical error of ±49.6%, with 80% of held-out values landing inside the 95% band.19832029
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 →
20251.20.372.0
20261.20.402.0
20271.20.422.0
20281.20.442.0
20291.30.472.1

Routes In BCR 4

Routes recording Trumpeter Swan 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 →
Mud RiverALASKA102022
NorthwayALASKA72023
Nicholai SlALASKA62024
Galena (Short)ALASKA62024
SlanaALASKA52024
PetersvilleALASKA52008
CircleALASKA42024
ChistochinaALASKA42022
Seven LakesALASKA42012
Kanuti CanynALASKA42016
McgrathALASKA42022
Kanuti LakeALASKA32024
Tower BluffsALASKA22023
CantwellALASKA22015
TonsinaALASKA22021
Donelly DomeALASKA22017
Paxson LakeALASKA21997
Nabesna RoadALASKA22024
Birch LakeALASKA12022
MaclarenALASKA12024
MonahanALASKA12021
Kenny LakeALASKA12013
SourdoughALASKA12023
Swan Lake RdALASKA12015
Chena Hot Spring 2ALASKA12022

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