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

Violet-green Swallow Population Trend in Nevada

All statesAerial insectivores

Violet-green Swallow in Nevada has fallen sharply: down 70% on the route-weighted index since 1970.

-70%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 →
32Routes 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 →
42YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Violet-green Swallow Trends in NevadaNotable 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 →

Violet-green Swallow has fallen sharply in Nevada: down 70% on the route-weighted index since 1970.

Violet-green Swallow Population Forecast in Nevada

If the recent trend holds, Violet-green Swallow in Nevada is projected to fall about 69% by 2029 — from 2.4 in 2024 to a central estimate of 0.75 (95% range 0.00–4.6). A 5-year backtest shows a typical error of ±231.9%, with 100% of held-out values landing inside the 95% band.

-69%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 →
0.75Projected 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 →
0.00–4.695% 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 →
±231.9%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, Violet-green Swallow in Nevada is projected to fall about 69% by 2029 — from 2.4 in 2024 to a central estimate of 0.75 (95% range 0.00–4.6). A 5-year backtest shows a typical error of ±231.9%, 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 →
20250.810.004.7
20260.800.004.7
20270.780.004.7
20280.760.004.6
20290.750.004.6

Violet-green Swallow Survey Routes in Nevada

Routes recording Violet-green Swallow in Nevada.
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 →
Meadow Vally6020241996
Ranchogrande2219911991
Rye Patch1019741969
Cortez819721968
Calico Spr719741969
Comins Lake620162005
Virgin Creek620172000
Minerva620051989
Fish Creek420062006
Ruby Valley 2420242016
Willis419981995
Hiko420231969
Hawthorne420011999
Toiyabe Nf320182013
Humboldt Nf220181993
Austin220182009
Ash Meadows219951995
Illipah219681968
Nelson219971997
Jarbidge220152006
Ruby Valley219971997
Bald Mtn.220241996
Gardnerville 2220242024
Desert Nwr120131992
Midas120122012

Violet-green Swallow Population Trend in Other States

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