BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Acadian Flycatcher Population Analysis

TyrannidaeAerial insectivoresEmpidonax virescens

Acadian Flycatcher has increased: up 32% on the route-weighted index since 1968.

+32%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 →
1,572RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
59Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Acadian Flycatcher

The Acadian Flycatcher (Empidonax virescens) is a North American member of the Tyrant Flycatchers (Tyrannidae). In this analysis it is grouped with the aerial insectivores.

Size
4.5–9 in long (12–23 cm) — a small to medium flycatcher (typical for the family)
Habitat
Open airspace over fields, water and towns; nests in cavities, earthen banks or on structures.
Diet
Flying insects caught on the wing.
Range
Recorded on 1,572 Breeding Bird Survey routes across 32 states, most concentrated in the Appalachian Mountains.
Family
Tyrannidae · Aerial insectivores

Notable Acadian Flycatcher TrendsNotable 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 Acadian Flycatcher. See the full index history below.

Acadian Flycatcher Population Forecast

If the recent trend holds, Acadian Flycatcher is projected to stay roughly flat through 2030, near 1.3 (95% range 1.1–1.6). A 5-year backtest shows a typical error of ±8.3%, with 100% of held-out values landing inside the 95% band.

+3%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 →
1.3Projected 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 →
1.1–1.695% 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 →
±8.3%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 is projected to stay roughly flat through 2030, near 1.3 (95% range 1.1–1.6). A 5-year backtest shows a typical error of ±8.3%, with 100% 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 →
20261.31.11.5
20271.31.11.6
20281.31.11.6
20291.31.11.6
20301.31.11.6

Where the Acadian Flycatcher Is Detected

BBS routes recording Acadian Flycatcher, sized by most recent count.

Acadian Flycatcher Population Trend by State

Acadian Flycatcher population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alabama+157%196899
Arkansas+57%196955
Connecticut+138%198312
Delaware+217%196816
Florida-32%196847
Georgia+33%1968101
Illinois+404%196863
Indiana+113%196857
Iowa+15%19708
Kansas+219%197113
Kentucky+70%196862
Louisiana+342%196976
Maryland+172%196876
Massachusettsinsufficient datan/a4
Michigan+447%196937
Minnesotainsufficient datan/a2
Mississippi19×196864
Missouri11×197173
New Hampshireinsufficient datan/a2
New Jersey+599%196927
New York+181%197822
North Carolina+149%1968109
Ohio+292%196875
Oklahoma+144%196927
Pennsylvania+249%1968112
Rhode Islandinsufficient datan/a2
South Carolina+6%196851
Tennessee+208%196853
Texas-25%196958
Virginia+76%196888
West Virginia-7%196864
Wisconsin+28%197417

Acadian Flycatcher Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Acadian Flycatcher population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Lower Great Lakes / St. Lawrence Plain+164%196836
Edwards Plateau-32%19737
Oaks and Prairies-2%197028
Eastern Tallgrass Prairie+146%1968153
Prairie Hardwood Transition+278%196969
Central Hardwoods+148%1968157
West Gulf Coastal Plain / Ouachitas+18%1969106
Mississippi Alluvial Valley+283%196952
Southeastern Coastal Plain+174%1968317
Appalachian Mountains+82%1968350
Piedmont+98%1968155
New England / Mid-Atlantic Coast+149%1968109
Peninsular Florida-83%196812
Gulf Coastal Prairie-23%198213

Acadian Flycatcher Conservation Status

Our route-weighted index shows it up about 32% since 1968. Aerial insectivores have fallen sharply across the continent, a decline widely linked to dwindling insect prey.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.