BirdAnalyst
Species · North Carolina · BBS 2026 Release · 1966–2025

Cliff Swallow Population Trend in North Carolina

All statesAerial insectivores

Cliff Swallow in North Carolina has surged: up 164% on the route-weighted index since 1973.

+164%Since 1973TrendPercent 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 →
25Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Cliff Swallow Trends in North CarolinaNotable 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 increasecomputed 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 →

Cliff Swallow has surged in North Carolina: up 164% on the route-weighted index since 1973.

Cliff Swallow Population Forecast in North Carolina

If the recent trend holds, Cliff Swallow in North Carolina is projected to fall about 54% by 2030 — from 4.5 in 2025 to a central estimate of 2.1 (95% range 0.00–4.7). A 5-year backtest shows a typical error of ±33.4%, with 80% of held-out values landing inside the 95% band.

-54%Change by 2030TrendPercent 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 →
2.1Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–4.795% 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 →
±33.4%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, Cliff Swallow in North Carolina is projected to fall about 54% by 2030 — from 4.5 in 2025 to a central estimate of 2.1 (95% range 0.00–4.7). A 5-year backtest shows a typical error of ±33.4%, with 80% of held-out values landing inside the 95% band.19712030
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 →
20262.00.004.6
20272.00.004.7
20282.00.004.7
20292.00.004.7
20302.10.004.7

Cliff Swallow Survey Routes in North Carolina

Routes recording Cliff Swallow in North Carolina.
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 →
Arcola9320251971
Fairview7020252005
Call5420251972
Eden1520252019
Siloam1320252005
Marshall1220252009
Hamlet620222019
Merrimon520232021
Copeland520252021
Oakboro420252008
Mount Airy420242024
Mooresville319961994
French Broad River320232023
Newport320192018
Bullock320251997
Mooresville 2320252010
Uwharrie Nf219971997
Climax220222022
Sturgills220222022
Osmond220052005
Hulls Xroads220232008
Flay220001994
Dortches120072005
Monticello120252018
Todd120232023

Cliff Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.