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

Purple Martin Population Trend in Colorado

All statesAerial insectivores

Purple Martin in Colorado has edged up: up 15% on the route-weighted index since 1988.

+15%Since 1988TrendPercent 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 →
25Routes 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 →
35YearsYears 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 ColoradoNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Purple Martin in Colorado. See the full index history below.

Purple Martin Population Forecast in Colorado

If the recent trend holds, Purple Martin in Colorado is projected to rise about 116% by 2029 — from 0.15 in 2024 to a central estimate of 0.34 (95% range 0.05–0.62). A 5-year backtest shows a typical error of ±119.2%, with 100% of held-out values landing inside the 95% band.

+116%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 →
0.34Projected 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 →
0.05–0.6295% 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 →
±119.2%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 Colorado is projected to rise about 116% by 2029 — from 0.15 in 2024 to a central estimate of 0.34 (95% range 0.05–0.62). A 5-year backtest shows a typical error of ±119.2%, 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 →
20250.320.040.60
20260.320.040.60
20270.330.040.61
20280.330.050.61
20290.340.050.62

Purple Martin Survey Routes in Colorado

Routes recording Purple Martin in Colorado.
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 →
Ragged Mtn.1520191996
Uncompahgre1020241988
Colona 2620212015
Haycamp Mesa520102003
Villegreen419981998
Dolores319681968
Bethune320152015
Flattops320181994
Groundhog Rs320241996
Yampa220182018
Douglas Pass220222022
Lay220232023
Thomasville220172005
Yellowjacket Pass219981998
Cokedale220242024
Buford119961985
Delta120052002
Colona120141996
Willow Peak120162013
Castleton120131998
Dunckley Pas120221993
Paonia120171999
Rifle Falls120021999
Nucla120102010
Owl Creek Pass120002000

Purple Martin Population Trend in Other States

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

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