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Species · Utah · BBS 2026 Release · 1966–2025

Tree Swallow Population Trend in Utah

All statesAerial insectivores

Tree Swallow in Utah has collapsed: down 80% on the route-weighted index since 1970.

-80%Since 1970TrendPercent 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 StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56YearsYears 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 UtahNotable 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 →

Tree Swallow has collapsed in Utah: down 80% on the route-weighted index since 1970.

Tree Swallow Population Forecast in Utah

If the recent trend holds, Tree Swallow in Utah is projected to fall about 95% by 2030 — from 1.1 in 2025 to a central estimate of 0.06 (95% range 0.00–3.4). A 5-year backtest shows a typical error of ±81%, with 100% of held-out values landing inside the 95% band.

-95%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 →
0.06Projected 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 →
0.00–3.495% 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 →
±81%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 Utah is projected to fall about 95% by 2030 — from 1.1 in 2025 to a central estimate of 0.06 (95% range 0.00–3.4). A 5-year backtest shows a typical error of ±81%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.280.003.7
20270.220.003.6
20280.170.003.6
20290.110.003.5
20300.060.003.4

Tree Swallow Survey Routes in Utah

Routes recording Tree Swallow in Utah.
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 →
Monticello1920241999
Hanna1720241997
Beck1519871968
M Warner Res1420251993
Skyline Driv1420251986
La Sal1419981994
Logan Canyon1020191997
Shivwitz1020252000
Uintah Nf919941987
Fish Lake Nf920251994
Oak City820161980
Hardware Ranch820161994
Lost Cr. Res720181995
Richfield720181996
Gooseberry720251994
Altonah620151971
Heber Mtn.620251996
Book Ridge520212021
Wellington 2520072007
Ferron520222002
Beck 2420251990
Vernal420182004
Alton420062000
Escalante420051999
Wasatch Nf420241988

Tree Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.