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Species · New Jersey · BBS 2025 Release · 1966–2024

Alder Flycatcher Population Trend in New Jersey

All statesAerial insectivores

Alder Flycatcher in New Jersey has edged down: down 10% on the route-weighted index since 1987.

-10%Since 1987TrendPercent 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 StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
23YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Alder Flycatcher Trends in New JerseyNotable 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 Alder Flycatcher in New Jersey. See the full index history below.

Alder Flycatcher Population Forecast in New Jersey

If the recent trend holds, Alder Flycatcher in New Jersey is projected to stay roughly flat through 2029, near 0.05 (95% range 0.00–0.10). A 5-year backtest shows a typical error of ±29.8%, 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 →
0.05Projected 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 →
0.00–0.1095% 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 →
±29.8%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 New Jersey is projected to stay roughly flat through 2029, near 0.05 (95% range 0.00–0.10). A 5-year backtest shows a typical error of ±29.8%, with 100% of held-out values landing inside the 95% band.19772029
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 →
20250.050.000.11
20260.050.000.11
20270.050.000.11
20280.050.000.10
20290.050.000.10

Alder Flycatcher Survey Routes in New Jersey

Routes recording Alder Flycatcher in New Jersey.
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 →
Sandbrook119771977
Midvale119801980
Kemah Lake120052005
Ramseysburg120112006
High Point120241987
Dover120002000
Roosevelt119951995

Alder Flycatcher Population Trend in Other States

alaskaconnecticutidahoillinoisindianaiowamainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-dakotavermontvirginiawashingtonwest-virginiawisconsin

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