BirdAnalyst
Species · Indiana · BBS 2025 Release · 1966–2024

Tree Swallow Population Trend in Indiana

All statesAerial insectivores

Tree Swallow in Indiana has surged: up 699% on the route-weighted index since 1976.

+699%Since 1976TrendPercent 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 →
67Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
48YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Tree Swallow Trends in IndianaNotable 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 Indiana: up 699% on the route-weighted index since 1976.

Tree Swallow Population Forecast in Indiana

If the recent trend holds, Tree Swallow in Indiana is projected to stay roughly flat through 2029, near 4.4 (95% range 2.4–6.4). A 5-year backtest shows a typical error of ±46.6%, with 80% of held-out values landing inside the 95% band.

+4%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 →
4.4Projected 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 →
2.4–6.495% 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 →
±46.6%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 Indiana is projected to stay roughly flat through 2029, near 4.4 (95% range 2.4–6.4). A 5-year backtest shows a typical error of ±46.6%, 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 →
20254.02.06.0
20264.12.16.1
20274.22.26.2
20284.32.36.3
20294.42.46.4

Tree Swallow Survey Routes in Indiana

Routes recording Tree Swallow in Indiana.
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 →
Lagrange4720241999
Ellis4220241966
Newberry2020242002
Lakeville1720171993
Belmont1520211983
Cross Plains1120242000
Cyprss1120192007
Indiana Dune1120241993
Jamestown920192003
Galveston820241994
Sexton820242023
Cuba720212017
Portage 2720232005
Berne620242001
Pimento620241998
Spencer620242004
Millersburg620241994
Celestine620241988
Kankakee Sands620242000
Portage620042000
Middlebury520241989
Columbia Cty520231981
W Lafayette520241990
Cumback520171983
Shelbyville420242001

Tree Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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