BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Olive-sided Flycatcher

TyrannidaeAerial insectivoresContopus cooperi

Olive-sided Flycatcher has surged: up 171% on the route-weighted index since 1968.

+171%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 →
961RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years 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 Olive-sided Flycatcher

The Olive-sided Flycatcher (Contopus cooperi) 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 961 Breeding Bird Survey routes across 26 states, most concentrated in the Northern Pacific Rainforest.
Family
Tyrannidae · Aerial insectivores

Notable Olive-sided 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 →

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 →

Olive-sided Flycatcher has surged in surveyed states: up 171% on the route-weighted index since 1968.

Olive-sided Flycatcher Population Forecast

If the recent trend holds, Olive-sided Flycatcher is projected to stay roughly flat through 2029, near 0.33 (95% range 0.14–0.52). A 5-year backtest shows a typical error of ±26.3%, with 100% of held-out values landing inside the 95% band.

+9%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 →
0.33Projected 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 →
0.14–0.5295% 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 →
±26.3%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, Olive-sided Flycatcher is projected to stay roughly flat through 2029, near 0.33 (95% range 0.14–0.52). A 5-year backtest shows a typical error of ±26.3%, with 100% 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 →
20250.340.140.53
20260.330.140.53
20270.330.140.53
20280.330.140.52
20290.330.140.52

Where the Olive-sided Flycatcher Is Detected

BBS routes recording Olive-sided Flycatcher, sized by most recent count.

Olive-sided Flycatcher Population Trend by State

Olive-sided 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 →
Alaska+107%197591
Arizona+31%197319
California-56%1970158
Colorado-40%197079
Idaho+76%197234
Maine-90%196968
Marylandinsufficient datan/a1
Massachusettsinsufficient datan/a4
Michigan-26%196836
Minnesota-31%197045
Montana+16%197042
Nevadainsufficient datan/a4
New Hampshire-90%196821
New Mexico+42%197215
New York-66%196826
North Carolinainsufficient datan/a1
Ohioinsufficient datan/a1
Oregon-74%197099
Pennsylvaniainsufficient datan/a7
South Dakotainsufficient datan/a1
Utah-77%198143
Vermont-75%196920
Washington-59%197076
West Virginiainsufficient datan/a1
Wisconsin-81%196841
Wyoming+93%197828

Olive-sided Flycatcher Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Olive-sided 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 →
BCR 4+50%198260
Northern Pacific Rainforest-77%1970149
Great Basin-36%197086
Northern Rockies-13%1970126
Boreal Hardwood Transition-39%196898
Atlantic Northern Forest-91%1968128
Sierra Nevada-80%197038
Southern Rockies / Colorado Plateau-14%1970131
Prairie Hardwood Transition-29%197020
Coastal California-56%197064
Sonoran and Mojave Deserts-34%19743
Sierra Madre Occidental-56%197418

Olive-sided Flycatcher Conservation Status

Our route-weighted index shows it up about 171% 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 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.