BirdAnalyst
Species · BCR 28 · BBS 2026 Release · 1966–2025

Mourning Warbler In Appalachian Mountains

All regionsAppalachian MountainsForest birds

Mourning Warbler in Appalachian Mountains has risen sharply: up 63% on the route-weighted index since 1968.

+63%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 →
67Routes 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 →
59YearsYears 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 →

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 →

Mourning Warbler has risen sharply in Appalachian Mountains: up 63% on the route-weighted index since 1968.

Mourning Warbler In Appalachian Mountains Population Forecast

If the recent trend holds, Mourning Warbler in Appalachian Mountains is projected to rise about 48% by 2030 — from 0.09 in 2025 to a central estimate of 0.14 (95% range 0.07–0.21). A 5-year backtest shows a typical error of ±57.7%, with 80% of held-out values landing inside the 95% band.

+48%Change by 2030TrendPercent 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 →
0.14Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.07–0.2195% 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 →
±57.7%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 Appalachian Mountains is projected to rise about 48% by 2030 — from 0.09 in 2025 to a central estimate of 0.14 (95% range 0.07–0.21). A 5-year backtest shows a typical error of ±57.7%, with 80% of held-out values landing inside the 95% band.19662030
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 →
20260.130.070.20
20270.140.070.20
20280.140.070.20
20290.140.070.20
20300.140.070.21

Routes In Appalachian Mountains

Routes recording Mourning Warbler in Appalachian Mountains.
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 →
McdonoughNEW-YORK52017
ArnotPENNSYLVANIA42018
AnsoniaPENNSYLVANIA42025
MilfordNEW-YORK32022
OdinPENNSYLVANIA32025
WymerWEST-VIRGINIA32009
E NewarkNEW-YORK21996
DrydenNEW-YORK22021
CattaraugusNEW-YORK22019
East JavaNEW-YORK22018
Swain 2NEW-YORK22024
Little MarshPENNSYLVANIA22023
Cherry SprsPENNSYLVANIA22025
Mawr GlenPENNSYLVANIA22021
Marsh HillPENNSYLVANIA22013
Valley HeadWEST-VIRGINIA22018
DaileyWEST-VIRGINIA22025
GladyWEST-VIRGINIA22023
BemisWEST-VIRGINIA22023
FloydMARYLAND11996
VindexMARYLAND11997
SteyerMARYLAND12008
MeridaleNEW-YORK12025
Platte CoveNEW-YORK12016
LaurensNEW-YORK12024

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.