BirdAnalyst
Species · BCR 19 · BBS 2025 Release · 1966–2024

Chimney Swift In Central Mixed Grass Prairie

All regionsCentral Mixed Grass PrairieAerial insectivores

Chimney Swift in Central Mixed Grass Prairie has collapsed: down 80% on the route-weighted index since 1969.

-80%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 →
116Routes 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 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 →

Chimney Swift has collapsed in Central Mixed Grass Prairie: down 80% on the route-weighted index since 1969.

Forecast

If the recent trend holds, Chimney Swift in Central Mixed Grass Prairie is projected to fall about 85% by 2029 — from 0.91 in 2024 to a central estimate of 0.14 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±59.5%, with 100% of held-out values landing inside the 95% band.

-85%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 →
0.14Projected 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 →
0.00–1.395% 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 →
±59.5%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, Chimney Swift in Central Mixed Grass Prairie is projected to fall about 85% by 2029 — from 0.91 in 2024 to a central estimate of 0.14 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±59.5%, 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 →
20250.370.001.5
20260.310.001.4
20270.250.001.4
20280.200.001.3
20290.140.001.3

Routes In Central Mixed Grass Prairie

Routes recording Chimney Swift in Central Mixed Grass 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 →
Liberty 2NEBRASKA402007
VerdenOKLAHOMA202004
ChapmanKANSAS161981
AlmeriaNEBRASKA152021
BartleyNEBRASKA112024
LibertyNEBRASKA102003
MullenNEBRASKA102017
SewardNEBRASKA82024
CovertKANSAS72022
ElginOKLAHOMA71994
LeovilleKANSAS62015
StrattonNEBRASKA62024
WilliamsTEXAS62023
WellingtonKANSAS52024
AlbertKANSAS52021
ArapahoOKLAHOMA52012
HackberryTEXAS52022
AshlandKANSAS42021
BelvidereNEBRASKA42024
ArthurNEBRASKA42024
BerwynNEBRASKA41997
CookietownOKLAHOMA42006
RosstonOKLAHOMA42017
SicklesOKLAHOMA42021
GraybackTEXAS42005

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