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Species · Maryland · BBS 2025 Release · 1966–2024

Alder Flycatcher Population Trend in Maryland

All statesAerial insectivores

Alder Flycatcher in Maryland has edged down: down 21% on the route-weighted index since 1978.

-21%Since 1978TrendPercent 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 →
5Routes 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 →
43YearsYears 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 MarylandNotable 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 Maryland. See the full index history below.

Alder Flycatcher Population Forecast in Maryland

If the recent trend holds, Alder Flycatcher in Maryland is projected to stay roughly flat through 2027, near 0.05 (95% range 0.00–0.10). A 5-year backtest shows a typical error of ±66.1%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2027TrendPercent 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 2027 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 →
±66.1%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 Maryland is projected to stay roughly flat through 2027, near 0.05 (95% range 0.00–0.10). A 5-year backtest shows a typical error of ±66.1%, with 100% of held-out values landing inside the 95% band.19732027
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 →
20230.050.000.10
20240.050.000.10
20250.050.000.10
20260.050.000.10
20270.050.000.10

Alder Flycatcher Survey Routes in Maryland

Routes recording Alder Flycatcher in Maryland.
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 →
Mt Nebo219731973
Steyer220221997
Vindex120211976
Jennings119981995
Finzel120171995

Alder Flycatcher Population Trend in Other States

alaskaconnecticutidahoillinoisindianaiowamainemassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-dakotavermontvirginiawashingtonwest-virginiawisconsin

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