BirdAnalyst
Species · BCR 30 · BBS 2025 Release · 1966–2024

Cliff Swallow In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastAerial insectivores

Cliff Swallow in New England / Mid-Atlantic Coast has edged up: up 24% on the route-weighted index since 1968.

+24%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 →
25Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
49YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 Cliff Swallow in New England / Mid-Atlantic Coast. See the full index history below.

Forecast

If the recent trend holds, Cliff Swallow in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2029, near 0.21 (95% range 0.00–0.43). A 5-year backtest shows a typical error of ±179.2%, with 80% of held-out values landing inside the 95% band.

n/aChange 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 →
0.21Projected 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 →
0.00–0.4395% 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 →
±179.2%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, Cliff Swallow in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2029, near 0.21 (95% range 0.00–0.43). A 5-year backtest shows a typical error of ±179.2%, with 80% 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 →
20250.200.000.42
20260.200.000.42
20270.200.000.42
20280.200.000.43
20290.210.000.43

Routes In New England / Mid-Atlantic Coast

Routes recording Cliff Swallow in New England / Mid-Atlantic Coast.
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 →
Port RoyalVIRGINIA522019
Kittery PtMAINE101994
PurdyNEW-YORK82022
WarrenCONNECTICUT72004
E PepperellMASSACHUSETTS51981
Cape NeddickMAINE41975
BeltsvilleMARYLAND32010
DanburyCONNECTICUT22008
BlackbirdDELAWARE22024
PomfretMARYLAND22000
MaynardMASSACHUSETTS21968
S BarreMASSACHUSETTS21994
BrentwoodNEW-HAMPSHIRE21985
ShermanCONNECTICUT12005
Long HillCONNECTICUT12019
Mid HaddamCONNECTICUT11986
Warren 2CONNECTICUT12021
GranbyCONNECTICUT11991
DavidsnvilleMARYLAND11995
PrincetonMASSACHUSETTS11969
BelchertownMASSACHUSETTS11992
WarrenMASSACHUSETTS11975
HoldenMASSACHUSETTS11983
DoverNEW-HAMPSHIRE12008
EpsomNEW-HAMPSHIRE12007

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