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

Purple Martin Population Trend in Wisconsin

All statesAerial insectivores

Purple Martin in Wisconsin has collapsed: down 89% on the route-weighted index since 1968.

-89%Since 1968TrendPercent 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 →
84Routes 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 →
58YearsYears 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 WisconsinNotable 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 collapsed in Wisconsin: down 89% on the route-weighted index since 1968.

Purple Martin Population Forecast in Wisconsin

If the recent trend holds, Purple Martin in Wisconsin is projected to fall about 100% by 2029 — from 1.1 in 2024 to a central estimate of 0.00 (95% range 0.00–2.7). A 5-year backtest shows a typical error of ±371%, with 20% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–2.795% 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 →
±371%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 Wisconsin is projected to fall about 100% by 2029 — from 1.1 in 2024 to a central estimate of 0.00 (95% range 0.00–2.7). A 5-year backtest shows a typical error of ±371%, with 20% of held-out values landing inside the 95% band.19662029
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 →
20250.000.002.7
20260.000.002.7
20270.000.002.7
20280.000.002.7
20290.000.002.7

Purple Martin Survey Routes in Wisconsin

Routes recording Purple Martin in Wisconsin.
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 →
Kiel2620222005
Pardeeville2120241967
Holland2020241999
Clintonville1120081972
Manitowoc920241966
Exeland719921968
Omro720011966
Newburg Crns620241967
N Freedom620241967
Omro 2620242002
Casco520241966
Rib Lake419891966
Cadott420241966
Brownsville420211966
Bayfield319931969
Hudson320231967
Loraine320211966
Popple River319941967
Hollister320021967
Gilmanton320241967
Stevens Pt320001967
Pt Washingtn320241966
Montreal219881975
Weyerhauser220231966
Couderay220081969

Purple Martin Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawyoming

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