BirdAnalyst
Species · Indiana · BBS 2026 Release · 1966–2025

Tree Swallow Population Trend in Indiana

All statesAerial insectivores

Tree Swallow in Indiana has surged: up 781% on the route-weighted index since 1976.

+781%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 →
49YearsYears 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 781% 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 rise about 29% by 2030 — from 3.4 in 2025 to a central estimate of 4.4 (95% range 2.4–6.4). A 5-year backtest shows a typical error of ±50.8%, with 100% of held-out values landing inside the 95% band.

+29%Change by 2030TrendPercent 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 2030 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 →
±50.8%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 rise about 29% by 2030 — from 3.4 in 2025 to a central estimate of 4.4 (95% range 2.4–6.4). A 5-year backtest shows a typical error of ±50.8%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20264.12.16.0
20274.22.26.1
20284.22.36.2
20294.32.36.3
20304.42.46.4

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 →
Ellis4220241966
Lagrange2520251999
Milroy2120252002
Lakeville1720171993
Belmont1520211983
Frankfort1220251999
Cross Plains1120242000
Knox920251989
Jamestown920192003
Cumback920251983
Newberry920252002
Galveston820241994
Sexton820242023
Witts Station820252000
Indiana Dune720251993
Hebron620251979
Middletown620251989
Berne620242001
Spencer620242004
Millersburg620241994
Kankakee Sands620252000
Portage620042000
Packertown 2620252005
Columbia Cty520231981
W Lafayette520241990

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 2026-08-14.