BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Boreal Owl

StrigidaeBirds of preyAegolius funereus

Boreal Owl has no long-term trend on record.

n/aSince n/aTrendPercent 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 →
19RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
18Years 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 Boreal Owl

The Boreal Owl (Aegolius funereus) is a North American member of the Owls (Strigidae). In this analysis it is grouped with the birds of prey.

Size
5–27.5 in long (13–70 cm) — a nocturnal raptor (typical for the family)
Habitat
Open country, woodlands, cliffs and wetlands, hunting from the air or a high perch.
Diet
Live prey — small mammals, birds, reptiles, fish and large insects (carrion for vultures).
Range
Recorded on 19 Breeding Bird Survey routes across 4 states, most concentrated in the BCR 4.
Family
Strigidae · Birds of prey

Notable Boreal Owl 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 Boreal Owl. See the full index history below.

Boreal Owl Population Forecast

If the recent trend holds, Boreal Owl is projected to stay roughly flat through 2028, near 0.00 (95% range 0.00–0.00). A 5-year backtest shows a typical error of ±64.1%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.00Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0095% 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 →
±64.1%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, Boreal Owl is projected to stay roughly flat through 2028, near 0.00 (95% range 0.00–0.00). A 5-year backtest shows a typical error of ±64.1%, with 100% of held-out values landing inside the 95% band.19852028
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 →
20240.000.000.00
20250.000.000.00
20260.000.000.00
20270.000.000.00
20280.000.000.00

Where the Boreal Owl Is Detected

BBS routes recording Boreal Owl, sized by most recent count.

Boreal Owl Population Trend by State

Boreal Owl 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 →
Alaska-72%199315
Coloradoinsufficient datan/a2
Idahoinsufficient datan/a1
Montanainsufficient datan/a1

Boreal Owl Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Boreal Owl 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 →
BCR 4-78%199313

Boreal Owl Conservation Status

Boreal Owl is tracked across BBS survey routes; no formal conservation-status flag is recorded here.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.