BirdAnalyst
Species · BCR 37 · BBS 2025 Release · 1966–2024

Lark Sparrow In Gulf Coastal Prairie

All regionsGulf Coastal PrairieGrassland birds

Lark Sparrow in Gulf Coastal Prairie has collapsed: down 76% on the route-weighted index since 1969.

-76%Since 1969TrendPercent 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 →
19Routes 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 →
51YearsYears 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 →

Lark Sparrow has collapsed in Gulf Coastal Prairie: down 76% on the route-weighted index since 1969.

Forecast

If the recent trend holds, Lark Sparrow in Gulf Coastal Prairie is projected to fall about 50% by 2029 — from 0.91 in 2024 to a central estimate of 0.45 (95% range 0.00–2.4). A 5-year backtest shows a typical error of ±53%, with 100% of held-out values landing inside the 95% band.

-50%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 →
0.45Projected 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 →
0.00–2.495% 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 →
±53%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 Gulf Coastal Prairie is projected to fall about 50% by 2029 — from 0.91 in 2024 to a central estimate of 0.45 (95% range 0.00–2.4). A 5-year backtest shows a typical error of ±53%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.540.002.5
20260.520.002.4
20270.490.002.4
20280.470.002.4
20290.450.002.4

Routes In Gulf Coastal Prairie

Routes recording Lark Sparrow in Gulf Coastal Prairie.
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 →
Lag AtascosaTEXAS122024
Loyola Beach 2TEXAS72024
Goliad PrairieTEXAS52015
Loyola BeachTEXAS42009
PetronilaTEXAS32018
Rock IslandTEXAS31967
IndianolaTEXAS21974
KatyTEXAS21973
BaysideTEXAS21994
San PedroTEXAS22023
Bayside 3TEXAS22017
L. Atascosa NwrTEXAS22022
Hinkles FerTEXAS11988
VanderbiltTEXAS11976
WinnieTEXAS11993
Oyster LakeTEXAS12021
Bayside 2TEXAS12001
McfaddinTEXAS12016
Padre Island PaisTEXAS12015

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