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

Chimney Swift Population Trend in Virginia

All statesAerial insectivores

Chimney Swift in Virginia has fallen sharply: down 61% on the route-weighted index since 1968.

-61%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 →
87Routes 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 →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Chimney Swift Trends in VirginiaNotable 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 →

Chimney Swift has fallen sharply in Virginia: down 61% on the route-weighted index since 1968.

Chimney Swift Population Forecast in Virginia

If the recent trend holds, Chimney Swift in Virginia is projected to stay roughly flat through 2029, near 3.5 (95% range 0.67–6.4). A 5-year backtest shows a typical error of ±16.2%, with 100% of held-out values landing inside the 95% band.

-7%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 →
3.5Projected 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 →
0.67–6.495% 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 →
±16.2%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, Chimney Swift in Virginia is projected to stay roughly flat through 2029, near 3.5 (95% range 0.67–6.4). A 5-year backtest shows a typical error of ±16.2%, 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 →
20254.01.26.9
20263.91.16.8
20273.80.936.6
20283.70.806.5
20293.50.676.4

Chimney Swift Survey Routes in Virginia

Routes recording Chimney Swift in Virginia.
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 →
Great Falls2119761966
Newsoms2020241967
Gladys1620241995
Hall1420231967
Wylliesburg1420191971
Blacksburg1420231988
Taylorstown1320101967
Port Royal1320191977
Edinburg1220241968
Ringgold1120241976
Stanley1020241966
Hebron1020221981
Dryden1020241991
Newbern919821968
Amherst820241967
White Stone820241966
Irisburg820241976
Brandy Station820242017
Tryme720191975
David620131968
Surry620241977
Quinby620241966
Ivanhoe619681966
Waverly519871967
Marion519821976

Chimney Swift Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontwest-virginiawisconsinwyoming

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