BirdAnalyst
Species · North Dakota · BBS 2025 Release · 1966–2024

Purple Martin Population Trend in North Dakota

All statesAerial insectivores

Purple Martin in North Dakota has surged: up 241% on the route-weighted index since 1969.

+241%Since 1969TrendPercent 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 →
31Routes 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 Purple Martin Trends in North DakotaNotable 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 →

Purple Martin has surged in North Dakota: up 241% on the route-weighted index since 1969.

Purple Martin Population Forecast in North Dakota

If the recent trend holds, Purple Martin in North Dakota is projected to rise about 30% by 2029 — from 0.93 in 2024 to a central estimate of 1.2 (95% range 0.48–1.9). A 5-year backtest shows a typical error of ±14.8%, with 100% of held-out values landing inside the 95% band.

+30%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 →
1.2Projected 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 →
0.48–1.995% 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 →
±14.8%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, Purple Martin in North Dakota is projected to rise about 30% by 2029 — from 0.93 in 2024 to a central estimate of 1.2 (95% range 0.48–1.9). A 5-year backtest shows a typical error of ±14.8%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20251.10.431.9
20261.20.451.9
20271.20.461.9
20281.20.471.9
20291.20.481.9

Purple Martin Survey Routes in North Dakota

Routes recording Purple Martin in North Dakota.
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 →
Turtle Mtns1920241980
Bowesmont1019951980
Cooperstown620031991
Niles520212000
Loraine520191985
Abercrombie520121967
Forman319921970
Danzig 2320232023
Walcott220211968
Rolla220221969
Carpio220011979
Wild Rose220242004
Powers Lake220182005
Braddock219911991
Edgeley119961982
Emerado120241973
Buchanan119791979
Nash120111980
Lakota120051972
Webster120162016
Dunn Center120242023
Tobacco120072005
Denbigh120132013
Bowman120222022
Zap120242024

Purple Martin Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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