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Species · Utah · BBS 2025 Release · 1966–2024

Purple Martin Population Trend in Utah

All statesAerial insectivores

Purple Martin in Utah has fallen sharply: down 63% on the route-weighted index since 1973.

-63%Since 1973TrendPercent 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 →
16Routes 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 →
41YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Purple Martin 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 →

Purple Martin has fallen sharply in Utah: down 63% on the route-weighted index since 1973.

Purple Martin Population Forecast in Utah

If the recent trend holds, Purple Martin in Utah is projected to fall about 22% by 2029 — from 0.09 in 2024 to a central estimate of 0.07 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±174.9%, with 100% of held-out values landing inside the 95% band.

-22%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 →
0.07Projected 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 →
0.00–0.2795% 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 →
±174.9%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, Purple Martin in Utah is projected to fall about 22% by 2029 — from 0.09 in 2024 to a central estimate of 0.07 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±174.9%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.080.000.28
20260.070.000.28
20270.070.000.28
20280.070.000.27
20290.070.000.27

Purple Martin Survey Routes in Utah

Routes recording Purple Martin 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 →
Saleratus Cr820041996
Promontory519741974
Woodruff420222002
Lost Cr. Res320161995
Aneth320242024
Beck219771971
Fish Lake Nf220242023
Soapstone220072007
Skyline Driv120151986
Richfield120191994
Logan Canyon120132001
Hardware Ranch120152015
Dragerton119691969
Red Spur Mtn.120222021
Beck 2120171991
Boulder119691969

Purple Martin Population Trend in Other States

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

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