BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Hammond's Flycatcher

TyrannidaeAerial insectivoresEmpidonax hammondii

Hammond's Flycatcher has surged: up 722% on the route-weighted index since 1970.

+722%Since 1970TrendPercent 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 →
483RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56Years 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 Hammond's Flycatcher

The Hammond's Flycatcher (Empidonax hammondii) 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 483 Breeding Bird Survey routes across 11 states, most concentrated in the Northern Rockies.
Family
Tyrannidae · Aerial insectivores

Notable Hammond's 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 Hammond's Flycatcher. See the full index history below.

Hammond's Flycatcher Population Forecast

If the recent trend holds, Hammond's Flycatcher is projected to rise about 25% by 2029 — from 0.41 in 2024 to a central estimate of 0.52 (95% range 0.39–0.64). A 5-year backtest shows a typical error of ±33%, with 40% of held-out values landing inside the 95% band.

+25%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 →
0.52Projected 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 →
0.39–0.6495% 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 →
±33%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, Hammond's Flycatcher is projected to rise about 25% by 2029 — from 0.41 in 2024 to a central estimate of 0.52 (95% range 0.39–0.64). A 5-year backtest shows a typical error of ±33%, with 40% of held-out values landing inside the 95% band.19682029
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 →
20250.490.370.61
20260.500.370.62
20270.500.380.63
20280.510.390.64
20290.520.390.64

Where the Hammond's Flycatcher Is Detected

BBS routes recording Hammond's Flycatcher, sized by most recent count.

Hammond's Flycatcher Population Trend by State

Hammond's 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+134%198744
Arizonainsufficient datan/a3
California+493%197076
Colorado+390%197469
Idaho+61%197838
Montana+351%197041
New Mexico+62%197310
Oregon+134%197085
Utah+234%198724
Washington+152%197071
Wyoming+637%198422

Hammond's Flycatcher Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Hammond's 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+225%198735
Northern Pacific Rainforest+127%197093
Great Basin+149%197076
Northern Rockies+230%1970127
Sierra Nevada-25%197235
Southern Rockies / Colorado Plateau+544%1970102
Coastal California+102%19827

Hammond's Flycatcher Conservation Status

Our route-weighted index shows it up about 722% since 1970. 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.