BirdAnalyst
Species · BCR 10 · BBS 2026 Release · 1966–2025

Lark Sparrow In Northern Rockies

All regionsNorthern RockiesGrassland birds

Lark Sparrow in Northern Rockies has risen sharply: up 64% on the route-weighted index since 1970.

+64%Since 1970TrendPercent 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 →
126Routes 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 →
57YearsYears 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 →

Lark Sparrow has risen sharply in Northern Rockies: up 64% on the route-weighted index since 1970.

Lark Sparrow In Northern Rockies Population Forecast

If the recent trend holds, Lark Sparrow in Northern Rockies is projected to fall about 16% by 2030 — from 1.9 in 2025 to a central estimate of 1.6 (95% range 0.73–2.5). A 5-year backtest shows a typical error of ±15.7%, with 100% of held-out values landing inside the 95% band.

-16%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 →
1.6Projected 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 →
0.73–2.595% 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 →
±15.7%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, Lark Sparrow in Northern Rockies is projected to fall about 16% by 2030 — from 1.9 in 2025 to a central estimate of 1.6 (95% range 0.73–2.5). A 5-year backtest shows a typical error of ±15.7%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20261.60.692.4
20271.60.702.4
20281.60.712.4
20291.60.722.5
20301.60.732.5

Routes In Northern Rockies

Routes recording Lark Sparrow in Northern Rockies.
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 →
LysiteWYOMING472024
Browns ParkCOLORADO392025
GeboWYOMING282025
TensleepWYOMING272025
BasinWYOMING232025
Muddy CreekMONTANA182015
LovellWYOMING162025
TwickenhamOREGON102025
OttoWYOMING102025
NowoodWYOMING102025
WorlandWYOMING102025
Sand DrawWYOMING102025
LayCOLORADO92025
MadrasOREGON92025
Patrick Draw 4WYOMING92002
MonumentOREGON82025
CrowheartWYOMING72021
CascadeIDAHO61983
Crane CreekIDAHO62019
MidvaleWYOMING62025
SweetwaterWYOMING62017
HarmonyWYOMING62008
MaybellCOLORADO52025
VictorMONTANA51996
DonnybrookOREGON51997

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