BirdAnalyst
Species · BCR 4 · BBS 2026 Release · 1966–2025

Savannah Sparrow In BCR 4

All regionsBCR 4Grassland birds

Savannah Sparrow in BCR 4 has fallen sharply: down 67% on the route-weighted index since 1977.

-67%Since 1977TrendPercent 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 →
63Routes 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 →
47YearsYears 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 declinecomputed 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 →

Savannah Sparrow has fallen sharply in BCR 4: down 67% on the route-weighted index since 1977.

Savannah Sparrow In BCR 4 Population Forecast

If the recent trend holds, Savannah Sparrow in BCR 4 is projected to fall about 24% by 2030 — from 3.8 in 2025 to a central estimate of 2.9 (95% range 0.00–10). A 5-year backtest shows a typical error of ±11.3%, with 100% of held-out values landing inside the 95% band.

-24%Change by 2030TrendPercent 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 →
2.9Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1095% 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 →
±11.3%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, Savannah Sparrow in BCR 4 is projected to fall about 24% by 2030 — from 3.8 in 2025 to a central estimate of 2.9 (95% range 0.00–10). A 5-year backtest shows a typical error of ±11.3%, with 100% of held-out values landing inside the 95% band.19752030
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 →
20263.60.0011
20273.40.0011
20283.30.0010
20293.10.0010
20302.90.0010

Routes In BCR 4

Routes recording Savannah Sparrow 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 →
ToklatALASKA582024
WasillaALASKA411983
MaclarenALASKA322025
HomerALASKA311982
SavageALASKA282025
KalifonskyALASKA162025
DeltaALASKA132024
Skilak LakeALASKA111985
SourdoughALASKA112025
Goose BayALASKA101982
Pinoche Tral (Short)ALASKA91984
CottonwoodALASKA71990
Ft. RichrdsnALASKA72023
Hather CreekALASKA62024
McgrathALASKA62022
KachemakALASKA52025
Caribou Mtn.ALASKA52025
Donelly DomeALASKA52025
KuskulanaALASKA52025
ChistochinaALASKA42025
TonsinaALASKA42021
CohoeALASKA42023
PetersvilleALASKA42025
Galena (Short)ALASKA42025
CircleALASKA32019

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.