BirdAnalyst
Species · BCR 11 · BBS 2025 Release · 1966–2024

Mourning Warbler In Prairie Potholes

All regionsPrairie PotholesForest birds

Mourning Warbler in Prairie Potholes has declined: down 38% on the route-weighted index since 1981.

-38%Since 1981TrendPercent 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 →
7Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
37YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 Prairie Potholes. See the full index history below.

Forecast

If the recent trend holds, Mourning Warbler in Prairie Potholes is projected to stay roughly flat through 2029, near 0.03 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±37%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.03Projected 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 →
0.00–0.0795% 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 →
±37%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 Prairie Potholes is projected to stay roughly flat through 2029, near 0.03 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±37%, with 100% of held-out values landing inside the 95% band.19782029
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 →
20250.030.000.07
20260.030.000.07
20270.030.000.07
20280.030.000.07
20290.030.000.07

Routes In Prairie Potholes

Routes recording Mourning Warbler in Prairie Potholes.
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 MtnsNORTH-DAKOTA22024
GlyndonMINNESOTA12011
OkleeMINNESOTA11993
BeltramiMINNESOTA11981
ErieMINNESOTA11995
BadgerMINNESOTA12003
NashNORTH-DAKOTA11989

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