BirdAnalyst
Species · BCR 16 · BBS 2025 Release · 1966–2024

Black-chinned Sparrow In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauGeneralists

Black-chinned Sparrow in Southern Rockies / Colorado Plateau has collapsed: down 81% on the route-weighted index since 1973.

-81%Since 1973TrendPercent 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 →
15Routes 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 →
37YearsYears 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 →

Black-chinned Sparrow has collapsed in Southern Rockies / Colorado Plateau: down 81% on the route-weighted index since 1973.

Forecast

If the recent trend holds, Black-chinned Sparrow in Southern Rockies / Colorado Plateau is projected to fall about 100% by 2029 — from 0.06 in 2024 to a central estimate of 0.00 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±136.7%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.1295% 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 →
±136.7%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, Black-chinned Sparrow in Southern Rockies / Colorado Plateau is projected to fall about 100% by 2029 — from 0.06 in 2024 to a central estimate of 0.00 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±136.7%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.000.000.12
20260.000.000.12
20270.000.000.12
20280.000.000.12
20290.000.000.12

Routes In Southern Rockies / Colorado Plateau

Routes recording Black-chinned Sparrow in Southern Rockies / Colorado Plateau.
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 →
Claunch 2NEW-MEXICO62024
HanksvilleUTAH42016
McgaffeyNEW-MEXICO31997
BeckUTAH31968
Moquith MtnUTAH32023
ShivwitzUTAH32010
Mt TrumbullARIZONA21979
ToroweapARIZONA22021
La CienegaNEW-MEXICO22018
ClaunchNEW-MEXICO21998
MountainairNEW-MEXICO22024
House RockARIZONA12013
The GapARIZONA11973
Horse MtnNEW-MEXICO12021
Navajo LakeUTAH11999

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