BirdAnalyst
Species · North Carolina · BBS 2025 Release · 1966–2024

Cliff Swallow Population Trend in North Carolina

All statesAerial insectivores

Cliff Swallow in North Carolina has surged: up 108% on the route-weighted index since 1973.

+108%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 →
51YearsYears 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 108% 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 48% by 2029 — from 3.5 in 2024 to a central estimate of 1.8 (95% range 0.00–4.4). A 5-year backtest shows a typical error of ±54.3%, with 60% of held-out values landing inside the 95% band.

-48%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 →
1.8Projected 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 →
0.00–4.495% 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 →
±54.3%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 48% by 2029 — from 3.5 in 2024 to a central estimate of 1.8 (95% range 0.00–4.4). A 5-year backtest shows a typical error of ±54.3%, with 60% of held-out values landing inside the 95% band.19712029
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 →
20251.80.004.3
20261.80.004.4
20271.80.004.4
20281.80.004.4
20291.80.004.4

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 →
Call9120241972
Marshall4020242009
Arcola3120241971
Copeland2020242021
Siloam1920242005
Fairview1420242005
Mooresville 21020242010
Oakboro620242008
Hamlet620222019
Merrimon520232021
Monticello420242018
Mount Airy420242024
Eden420242019
Mooresville319961994
French Broad River320232023
Newport320192018
Uwharrie Nf219971997
Climax220222022
Sturgills220222022
Osmond220052005
Hulls Xroads220232008
Flay220001994
Dortches120072005
Todd120232023
Bullock120231997

Cliff Swallow Population Trend in Other States

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

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