BirdAnalyst
Species · BCR 22 · BBS 2025 Release · 1966–2024

Least Flycatcher In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieAerial insectivores

Least Flycatcher in Eastern Tallgrass Prairie has fallen sharply: down 71% on the route-weighted index since 1969.

-71%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 →
66Routes 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 →
52YearsYears 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 →

No notable trend signals for Least Flycatcher in Eastern Tallgrass Prairie. See the full index history below.

Least Flycatcher In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Least Flycatcher in Eastern Tallgrass Prairie is projected to stay roughly flat through 2027, near 0.01 (95% range 0.00–0.03). A 5-year backtest shows a typical error of ±63.1%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2027TrendPercent 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 →
0.01Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0395% 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 →
±63.1%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, Least Flycatcher in Eastern Tallgrass Prairie is projected to stay roughly flat through 2027, near 0.01 (95% range 0.00–0.03). A 5-year backtest shows a typical error of ±63.1%, with 100% of held-out values landing inside the 95% band.19672027
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 →
20230.010.000.03
20240.010.000.03
20250.010.000.03
20260.010.000.03
20270.010.000.03

Routes In Eastern Tallgrass Prairie

Routes recording Least Flycatcher in Eastern Tallgrass 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 →
ChandlervillILLINOIS22002
MartinsvilleILLINOIS21983
AldenILLINOIS22019
ExlineIOWA21996
BedfordIOWA21972
PiersonIOWA21976
Mill CreekILLINOIS11984
HolcombILLINOIS11983
BarringtonILLINOIS11967
ItascaILLINOIS11997
GeneseoILLINOIS12017
StreatorILLINOIS11974
WayneILLINOIS12012
SherburnvillILLINOIS11967
New LenoxILLINOIS11982
WilliamsfldILLINOIS12011
Deer CreekILLINOIS12001
MackinawILLINOIS11971
DaileyILLINOIS12003
MilfordILLINOIS12001
MelroseILLINOIS11994
Bluff SpgsILLINOIS11971
ConcordILLINOIS11995
BelleviewILLINOIS12005
FairlandILLINOIS11995

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