BirdAnalyst
Species · New Jersey · BBS 2025 Release · 1966–2024

Northern Rough-winged Swallow Population Trend in New Jersey

All statesAerial insectivores

Northern Rough-winged Swallow in New Jersey has risen sharply: up 52% on the route-weighted index since 1969.

+52%Since 1969TrendPercent 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 →
27Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Northern Rough-winged Swallow Trends in New JerseyNotable 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 →

Northern Rough-winged Swallow has risen sharply in New Jersey: up 52% on the route-weighted index since 1969.

Northern Rough-winged Swallow Population Forecast in New Jersey

If the recent trend holds, Northern Rough-winged Swallow in New Jersey is projected to rise about 165% by 2029 — from 0.43 in 2024 to a central estimate of 1.1 (95% range 0.13–2.1). A 5-year backtest shows a typical error of ±94.6%, with 80% of held-out values landing inside the 95% band.

+165%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 →
1.1Projected 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 →
0.13–2.195% 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 →
±94.6%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, Northern Rough-winged Swallow in New Jersey is projected to rise about 165% by 2029 — from 0.43 in 2024 to a central estimate of 1.1 (95% range 0.13–2.1). A 5-year backtest shows a typical error of ±94.6%, with 80% of held-out values landing inside the 95% band.19672029
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 →
20251.10.122.1
20261.10.122.1
20271.10.122.1
20281.10.132.1
20291.10.132.1

Northern Rough-winged Swallow Survey Routes in New Jersey

Routes recording Northern Rough-winged Swallow in New Jersey.
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 →
Woodbury Hgt420211989
Midvale320211970
Kemah Lake320241981
Bloomsbury320241969
Gillette320191991
Ancora219701970
Sandbrook220241971
Dover220221980
Keyport220151990
Cranbury220221987
Cape May Ch220111994
Winslow220101990
Croton 2220232008
Greenwich120231967
Deepwater119771969
Toms River120151970
Albion120071975
Holmansville120091978
New Bedford120161972
Croton120031970
Hope119771974
High Point120231986
Pottersville120221987
Roosevelt120061997
Friendship120181981

Northern Rough-winged Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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