BirdAnalyst
Species · BCR 28 · BBS 2025 Release · 1966–2024

Alder Flycatcher In Appalachian Mountains

All regionsAppalachian MountainsAerial insectivores

Alder Flycatcher in Appalachian Mountains has surged: up 507% on the route-weighted index since 1970.

+507%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 →
133Routes 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 →
56YearsYears 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 →

Alder Flycatcher has surged in Appalachian Mountains: up 507% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Alder Flycatcher in Appalachian Mountains is projected to rise about 25% by 2029 — from 0.38 in 2024 to a central estimate of 0.48 (95% range 0.35–0.61). A 5-year backtest shows a typical error of ±43%, with 40% of held-out values landing inside the 95% band.

+25%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 →
0.48Projected 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 →
0.35–0.6195% 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 →
±43%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, Alder Flycatcher in Appalachian Mountains is projected to rise about 25% by 2029 — from 0.38 in 2024 to a central estimate of 0.48 (95% range 0.35–0.61). A 5-year backtest shows a typical error of ±43%, 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 →
20250.450.330.58
20260.460.330.59
20270.470.340.59
20280.470.350.60
20290.480.350.61

Routes In Appalachian Mountains

Routes recording Alder Flycatcher 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 →
DrydenNEW-YORK112024
Phillips CrNEW-YORK102024
Platte CoveNEW-YORK92018
Swain 2NEW-YORK82024
Little MarshPENNSYLVANIA82023
S Berne 2NEW-YORK72024
Roulette 2PENNSYLVANIA72023
MeridaleNEW-YORK62024
McdonoughNEW-YORK62017
MilfordNEW-YORK62023
EldredPENNSYLVANIA62015
RoulettePENNSYLVANIA52021
GladyWEST-VIRGINIA52024
MedusaNEW-YORK42023
S BerneNEW-YORK42013
LaurensNEW-YORK42024
OneontaNEW-YORK42024
RasselasPENNSYLVANIA42022
LoguePENNSYLVANIA42023
Marsh HillPENNSYLVANIA42024
StarlightPENNSYLVANIA41992
GreentownPENNSYLVANIA42024
EllentonPENNSYLVANIA42024
Vestal CtrNEW-YORK32018
CattaraugusNEW-YORK32019

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