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

Tree Swallow In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieAerial insectivores

Tree Swallow in Eastern Tallgrass Prairie has surged: up 940% on the route-weighted index since 1968.

+940%Since 1968TrendPercent 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 →
249Routes 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 →
58YearsYears 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 →

Tree Swallow has surged in Eastern Tallgrass Prairie: up 940% on the route-weighted index since 1968.

Tree Swallow In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Tree Swallow in Eastern Tallgrass Prairie is projected to rise about 26% by 2029 — from 1.7 in 2024 to a central estimate of 2.2 (95% range 1.5–2.8). A 5-year backtest shows a typical error of ±23.7%, with 80% of held-out values landing inside the 95% band.

+26%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 →
2.2Projected 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 →
1.5–2.895% 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 →
±23.7%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, Tree Swallow in Eastern Tallgrass Prairie is projected to rise about 26% by 2029 — from 1.7 in 2024 to a central estimate of 2.2 (95% range 1.5–2.8). A 5-year backtest shows a typical error of ±23.7%, with 80% of held-out values landing inside the 95% band.19662029
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 →
20252.01.32.7
20262.11.42.7
20272.11.42.8
20282.11.42.8
20292.21.52.8

Routes In Eastern Tallgrass Prairie

Routes recording Tree Swallow 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 →
Gretna 2NEBRASKA232023
PrairieburgIOWA162024
MarionOHIO162023
GeneseoILLINOIS152018
JanesvilleILLINOIS142024
SenecaILLINOIS132024
PittsburgKANSAS132012
FairburyILLINOIS122024
West LibertyIOWA112007
StreatorILLINOIS102024
GridleyILLINOIS102024
MelroseIOWA102024
KunkleOHIO102024
KentonOHIO102024
JamestownINDIANA92019
BryantIOWA92024
HudsonIOWA92022
Kings CreekOHIO92015
Le RoyILLINOIS82024
GalvestonINDIANA82024
SextonINDIANA82024
Queen CityMISSOURI82022
HolcombILLINOIS72023
WayneILLINOIS72024
Portage 2INDIANA72023

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