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Species · Maryland · BBS 2025 Release · 1966–2024

Acadian Flycatcher Population Trend in Maryland

All statesAerial insectivores

Acadian Flycatcher in Maryland has surged: up 181% on the route-weighted index since 1968.

+181%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 →
76Routes 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 →
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 Acadian 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 →

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 →

Acadian Flycatcher has surged in Maryland: up 181% on the route-weighted index since 1968.

Acadian Flycatcher Population Forecast in Maryland

If the recent trend holds, Acadian Flycatcher in Maryland is projected to fall about 15% by 2029 — from 9.8 in 2024 to a central estimate of 8.4 (95% range 6.6–10). A 5-year backtest shows a typical error of ±16%, with 40% of held-out values landing inside the 95% band.

-15%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 →
8.4Projected 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 →
6.6–1095% 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 →
±16%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, Acadian Flycatcher in Maryland is projected to fall about 15% by 2029 — from 9.8 in 2024 to a central estimate of 8.4 (95% range 6.6–10). A 5-year backtest shows a typical error of ±16%, with 40% 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 →
20258.06.29.8
20268.16.39.9
20278.26.49.9
20288.36.510
20298.46.610

Acadian Flycatcher Survey Routes in Maryland

Routes recording Acadian 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 →
Island Creek6720241991
Pomonkey5520241966
Earlton4820242014
Hughesville2420241966
Smithsburg1920141972
Davidsnville1920241982
La Plata1720091966
Pomfret1520241966
Millington1520241969
Wolfsville1420241966
Olney1420241966
Forest Grove1420232011
Pr Frederick1320241991
Pt Republic1219891966
Oldtown1120241970
Furnace Town1120242015
Tall Timbers1020141966
Madonna1020222009
Nottingham1020242005
St. George'S Island920172015
Jennings820241995
Cheltenham720041966
Broomes Isl719961966
Sinepuxent719781966
Green Ridge720241995

Acadian Flycatcher Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamassachusettsmichiganminnesotamississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvirginiawest-virginiawisconsin

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