BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Common Nighthawk In Coastal California

All regionsCoastal CaliforniaAerial insectivores

Common Nighthawk in Coastal California has collapsed: down 75% on the route-weighted index since 1970.

-75%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 →
16Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
33YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 declinecomputed 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 →

Common Nighthawk has collapsed in Coastal California: down 75% on the route-weighted index since 1970.

Common Nighthawk In Coastal California Population Forecast

If the recent trend holds, Common Nighthawk in Coastal California is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±117.6%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.01Projected 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 →
0.00–0.1295% 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 →
±117.6%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, Common Nighthawk in Coastal California is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±117.6%, 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 →
20250.010.000.13
20260.010.000.13
20270.010.000.13
20280.010.000.13
20290.010.000.12

Routes In Coastal California

Routes recording Common Nighthawk in Coastal 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 →
Red BluffCALIFORNIA32019
Big BearCALIFORNIA31986
FallsvaleCALIFORNIA21975
AnzaCALIFORNIA21970
MorenoCALIFORNIA12012
Lake SuccessCALIFORNIA11977
Point ReyesCALIFORNIA11974
CohassetCALIFORNIA12012
Green ValleyCALIFORNIA11975
Gold HillCALIFORNIA11980
OrovilleCALIFORNIA11990
TehamaCALIFORNIA12010
ReddingCALIFORNIA11983
CopperopolisCALIFORNIA12003
Angelus OaksCALIFORNIA11990
WoodlandsCALIFORNIA12024

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