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

Savannah Sparrow In BCR 4

All regionsBCR 4Grassland birds

Savannah Sparrow in BCR 4 has fallen sharply: down 66% on the route-weighted index since 1977.

-66%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 →
46YearsYears 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 66% 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 37% by 2029 — from 4.9 in 2024 to a central estimate of 3.1 (95% range 0.00–10). A 5-year backtest shows a typical error of ±20.8%, with 100% of held-out values landing inside the 95% band.

-37%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 →
3.1Projected 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 →
0.00–1095% 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 →
±20.8%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, Savannah Sparrow in BCR 4 is projected to fall about 37% by 2029 — from 4.9 in 2024 to a central estimate of 3.1 (95% range 0.00–10). A 5-year backtest shows a typical error of ±20.8%, with 100% of held-out values landing inside the 95% band.19752029
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 →
20253.80.0011
20263.60.0011
20273.50.0011
20283.30.0010
20293.10.0010

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
SavageALASKA372024
HomerALASKA311982
MonahanALASKA162021
KalifonskyALASKA152023
MaclarenALASKA132024
DeltaALASKA132024
CantwellALASKA112021
Skilak LakeALASKA111985
Goose BayALASKA101982
SourdoughALASKA92024
Pinoche Tral (Short)ALASKA91984
CottonwoodALASKA71990
Ft. RichrdsnALASKA72023
Caribou Mtn.ALASKA62024
Hather CreekALASKA62024
McgrathALASKA62022
Kenny LakeALASKA52024
PetersvilleALASKA52024
TonsinaALASKA42021
CohoeALASKA42023
Galena (Short)ALASKA42024
CircleALASKA32019
ChistochinaALASKA32024

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