BirdAnalyst
Species · California · BBS 2025 Release · 1966–2024

Lesser Nighthawk Population Trend in California

All statesAerial insectivores

Lesser Nighthawk in California has edged down: down 23% on the route-weighted index since 1970.

-23%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 →
55Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Lesser Nighthawk Trends in CaliforniaNotable 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 Lesser Nighthawk in California. See the full index history below.

Lesser Nighthawk Population Forecast in California

If the recent trend holds, Lesser Nighthawk in California is projected to fall about 25% by 2029 — from 0.20 in 2024 to a central estimate of 0.15 (95% range 0.00–0.42). A 5-year backtest shows a typical error of ±30.7%, with 100% 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 →
0.15Projected 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 →
0.00–0.4295% 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 →
±30.7%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, Lesser Nighthawk in California is projected to fall about 25% by 2029 — from 0.20 in 2024 to a central estimate of 0.15 (95% range 0.00–0.42). A 5-year backtest shows a typical error of ±30.7%, with 100% 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 →
20250.160.000.42
20260.160.000.42
20270.160.000.42
20280.150.000.42
20290.150.000.42

Lesser Nighthawk Survey Routes in California

Routes recording Lesser Nighthawk in California.
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 →
Coachella Cn5820001973
Imperial Dam1320101973
Palo Verde1120231973
Niland1020221973
Havasu Lake920031973
Greenwater V620241988
Rumsey620081969
Parker Dam620031973
Atwater520041974
Big Pine419891971
Willow Spgs419751968
Ivanpah420042000
Copperopolis419941972
Kelso Valley320242005
Ora Loma319811973
Lucerne Val319961989
Cuyamaca Pk320242016
Ventucopa220021984
Pennington219761976
Oroville220061991
Goldstone220041991
Valley Wells220172003
Bridgeport219741973
Anza Borrego220241969
Eureka Val220241992

Lesser Nighthawk Population Trend in Other States

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