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Species · Minnesota · BBS 2025 Release · 1966–2024

Mourning Warbler Population Trend in Minnesota

All statesForest birds

Mourning Warbler in Minnesota has increased: up 28% on the route-weighted index since 1969.

+28%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 →
45Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Mourning 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 →

No notable trend signals for Mourning Warbler in Minnesota. See the full index history below.

Mourning Warbler Population Forecast in Minnesota

If the recent trend holds, Mourning Warbler in Minnesota is projected to fall about 26% by 2029 — from 4.0 in 2024 to a central estimate of 2.9 (95% range 0.79–5.1). A 5-year backtest shows a typical error of ±38.1%, with 40% of held-out values landing inside the 95% band.

-26%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 →
2.9Projected 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 →
0.79–5.195% 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 →
±38.1%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, Mourning Warbler in Minnesota is projected to fall about 26% by 2029 — from 4.0 in 2024 to a central estimate of 2.9 (95% range 0.79–5.1). A 5-year backtest shows a typical error of ±38.1%, with 40% 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 →
20253.10.945.2
20263.00.905.2
20273.00.875.2
20283.00.835.1
20292.90.795.1

Mourning Warbler Survey Routes in Minnesota

Routes recording Mourning 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 →
Hart Lake3520241967
Lockport3120241967
Crane Lake2420241970
Glendale2420241993
Hovland2220241973
Sherry Lake2020221969
Chisholm1720242019
Jordan1520231993
Cromwell1120241967
Floodwood1020241967
Little Fork920241970
Sawbill Camp820241993
Nett Lake720242013
Mcgregor620241994
Bigfork620241993
Sawbill Lndg520241973
Island Lake520171967
Cohasset520221973
Bena519771977
Cass Lake420161981
Lude420231978
Nebish320191982
Blackduck320222004
Backus220141967
Evergreen220161969

Mourning Warbler Population Trend in Other States

connecticutillinoisindianamainemarylandmassachusettsmichigannew-hampshirenew-yorknorth-dakotaohiopennsylvaniavermontwest-virginiawisconsin

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