BirdAnalyst
Species · BCR 34 · BBS 2026 Release · 1966–2025

Cliff Swallow In Sierra Madre Occidental

All regionsSierra Madre OccidentalAerial insectivores

Cliff Swallow in Sierra Madre Occidental has fallen sharply: down 61% on the route-weighted index since 1971.

-61%Since 1971TrendPercent 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 →
23Routes 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 →
56YearsYears 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 →

long arc declinecomputed 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 fallen sharply in Sierra Madre Occidental: down 61% on the route-weighted index since 1971.

Cliff Swallow In Sierra Madre Occidental Population Forecast

If the recent trend holds, Cliff Swallow in Sierra Madre Occidental is projected to fall about 70% by 2030 — from 1.9 in 2025 to a central estimate of 0.58 (95% range 0.00–7.1). A 5-year backtest shows a typical error of ±83.2%, with 100% of held-out values landing inside the 95% band.

-70%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 →
0.58Projected 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 →
0.00–7.195% 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 →
±83.2%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 Sierra Madre Occidental is projected to fall about 70% by 2030 — from 1.9 in 2025 to a central estimate of 0.58 (95% range 0.00–7.1). A 5-year backtest shows a typical error of ±83.2%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.840.007.4
20270.780.007.3
20280.710.007.2
20290.650.007.2
20300.580.007.1

Routes In Sierra Madre Occidental

Routes recording Cliff Swallow in Sierra Madre Occidental.
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 →
Sunizona 2ARIZONA1002017
Skull Valley 2ARIZONA222025
Mormon LakeARIZONA141971
BlueARIZONA101989
WilliamsARIZONA102025
Carr MtnARIZONA102025
PomereneARIZONA82025
Skull ValleyARIZONA62024
AmadoARIZONA62018
MagdalenaNEW-MEXICO62024
SunizonaARIZONA21988
PinetopARIZONA22021
PrescottARIZONA12019
Peña BlancaARIZONA11994
PatagoniaARIZONA12014
Forest LakesARIZONA12025
CutterARIZONA12014
AlpineARIZONA12004
RedingtonARIZONA12025
McnealARIZONA12006
RuckerARIZONA11993
ReserveNEW-MEXICO12016
Emory PassNEW-MEXICO12004

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