BirdAnalyst
Species · New Jersey · BBS 2026 Release · 1966–2025

Tree Swallow Population Trend in New Jersey

All statesAerial insectivores

Tree Swallow in New Jersey has increased: up 42% on the route-weighted index since 1968.

+42%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 →
39Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Tree 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 →

No notable trend signals for Tree Swallow in New Jersey. See the full index history below.

Tree Swallow Population Forecast in New Jersey

If the recent trend holds, Tree Swallow in New Jersey is projected to rise about 41% by 2030 — from 2.7 in 2025 to a central estimate of 3.8 (95% range 1.3–6.4). A 5-year backtest shows a typical error of ±109.5%, with 80% of held-out values landing inside the 95% band.

+41%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 →
3.8Projected 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 →
1.3–6.495% 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 →
±109.5%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, Tree Swallow in New Jersey is projected to rise about 41% by 2030 — from 2.7 in 2025 to a central estimate of 3.8 (95% range 1.3–6.4). A 5-year backtest shows a typical error of ±109.5%, with 80% of held-out values landing inside the 95% band.19662030
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 →
20263.71.16.2
20273.71.26.2
20283.71.26.3
20293.81.26.3
20303.81.36.4

Tree Swallow Survey Routes in New Jersey

Routes recording Tree 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 →
Pomona1220251989
High Point1020251978
New Bedford720241969
Ramseysburg720251995
Deepwater519711969
Holmansville520091990
Midvale420161967
Dover420221993
Friendship420251979
Woodbury Hgt320252006
Six Points320251978
Toms River320241967
Bloomsbury320161969
Keyport320191990
Roosevelt320211992
Ocean City320251979
Greenwich220241966
Pottersville220231979
Gillette220251989
Villas219811980
Mt Misery219881987
Pedricktown 2220242014
Cape May Ch220132001
Spraguetown 3220212021
Bennett Mill 2220252016

Tree Swallow Population Trend in Other States

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

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