BirdAnalyst
Species · BCR 13 · BBS 2025 Release · 1966–2024

Mourning Warbler In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainForest birds

Mourning Warbler in Lower Great Lakes / St. Lawrence Plain has declined: down 44% on the route-weighted index since 1968.

-44%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 →
50Routes 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 →
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 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 Lower Great Lakes / St. Lawrence Plain. See the full index history below.

Forecast

If the recent trend holds, Mourning Warbler in Lower Great Lakes / St. Lawrence Plain is projected to rise about 120% by 2029 — from 0.08 in 2024 to a central estimate of 0.18 (95% range 0.00–0.47). A 5-year backtest shows a typical error of ±263.3%, with 100% of held-out values landing inside the 95% band.

+120%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 →
0.18Projected 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 →
0.00–0.4795% 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 →
±263.3%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 Lower Great Lakes / St. Lawrence Plain is projected to rise about 120% by 2029 — from 0.08 in 2024 to a central estimate of 0.18 (95% range 0.00–0.47). A 5-year backtest shows a typical error of ±263.3%, with 100% 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 →
20250.200.000.48
20260.190.000.48
20270.190.000.47
20280.190.000.47
20290.180.000.47

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Mourning Warbler in Lower Great Lakes / St. Lawrence Plain.
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 →
Alder CreekNEW-YORK42004
AkeleyPENNSYLVANIA41974
N VictoryNEW-YORK31972
DuanesburgNEW-YORK22018
Oriskany FlsNEW-YORK22024
RomulusNEW-YORK21975
OrleansNEW-YORK22015
SheridanNEW-YORK21997
N Victory 2NEW-YORK22002
N WilmurtNEW-YORK21998
EllenburgNEW-YORK22006
AusterlitzNEW-YORK12022
CayugaNEW-YORK11973
MacdougallNEW-YORK12001
BranchportNEW-YORK12012
Canadice LNEW-YORK12005
MendonNEW-YORK12019
Mt MorrisNEW-YORK12008
West SenecaNEW-YORK11974
CastileNEW-YORK12024
RandolphNEW-YORK12018
Cherry HillNEW-YORK12010
NashvilleNEW-YORK12002
E YoungstownNEW-YORK12002
ByronNEW-YORK12019

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