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

Tree Swallow Population Trend in Utah

All statesAerial insectivores

Tree Swallow in Utah has collapsed: down 82% on the route-weighted index since 1970.

-82%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 →
55YearsYears 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 82% 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 97% by 2029 — from 1.5 in 2024 to a central estimate of 0.05 (95% range 0.00–3.5). A 5-year backtest shows a typical error of ±81.6%, with 100% of held-out values landing inside the 95% band.

-97%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 →
0.05Projected 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 →
0.00–3.595% 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 →
±81.6%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 Utah is projected to fall about 97% by 2029 — from 1.5 in 2024 to a central estimate of 0.05 (95% range 0.00–3.5). A 5-year backtest shows a typical error of ±81.6%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.280.003.7
20260.220.003.6
20270.160.003.6
20280.100.003.5
20290.050.003.5

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 →
Grizzly Rdge2420241986
Monticello1920241999
Hanna1720241997
Beck1519871968
La Sal1419981994
Logan Canyon1020191997
Soapstone920221992
Uintah Nf919941987
Oak City820161980
Hardware Ranch820161994
Lost Cr. Res720181995
Boulder720021992
Richfield720181996
Altonah620151971
Woodruff620242002
Book Ridge520212021
M Warner Res520241993
Wellington 2520072007
Ferron520222002
Shivwitz420242000
Vernal420182004
Alton420062000
Escalante420051999
Wasatch Nf420241988
Hyrum319791975

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 2026-05-22.