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Species · Minnesota · BBS 2025 Release · 1966–2024

Cape May Warbler Population Trend in Minnesota

All statesForest birds

Cape May Warbler in Minnesota has surged: up 719% on the route-weighted index since 1970.

+719%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 →
26Routes 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 →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Cape May Warbler Trends in MinnesotaNotable 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 →

Cape May Warbler has surged in Minnesota: up 718% on the route-weighted index since 1970.

Cape May Warbler Population Forecast in Minnesota

If the recent trend holds, Cape May Warbler in Minnesota is projected to fall about 20% by 2029 — from 0.40 in 2024 to a central estimate of 0.32 (95% range 0.04–0.61). A 5-year backtest shows a typical error of ±59.4%, with 20% of held-out values landing inside the 95% band.

-20%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 →
0.32Projected 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 →
0.04–0.6195% 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 →
±59.4%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, Cape May Warbler in Minnesota is projected to fall about 20% by 2029 — from 0.40 in 2024 to a central estimate of 0.32 (95% range 0.04–0.61). A 5-year backtest shows a typical error of ±59.4%, with 20% 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 →
20250.300.020.59
20260.310.020.59
20270.310.030.60
20280.320.030.60
20290.320.040.61

Cape May Warbler Survey Routes in Minnesota

Routes recording Cape May Warbler in Minnesota.
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 →
Sawbill Camp1020241993
Lockport620241967
Jordan520231994
Sherry Lake420222018
Babbitt420172008
Cohasset320131988
Glendale320222010
Hart Lake220241969
Debs220241987
Crane Lake220231978
Blackduck220142014
Tamarac Nwr120021999
Nebish120192004
Cromwell120241991
Hovland120091986
Sawbill Lndg120241973
Floodwood120051983
Little Fork120131979
Lude119991980
Waskish119831983
Erie120092009
Nett Lake120182014
Brook Park120051998
Mcgregor120132001
Red Lake120152003

Cape May Warbler Population Trend in Other States

mainemichigannew-hampshirenew-yorkvermontwisconsin

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