BirdAnalyst
Species · BCR 34 · BBS 2025 Release · 1966–2024

Blue-gray Gnatcatcher In Sierra Madre Occidental

All regionsSierra Madre OccidentalForest birds

Blue-gray Gnatcatcher in Sierra Madre Occidental has risen sharply: up 64% on the route-weighted index since 1975.

+64%Since 1975TrendPercent 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 →
50YearsYears 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 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 →

Blue-gray Gnatcatcher has risen sharply in Sierra Madre Occidental: up 64% on the route-weighted index since 1975.

Blue-gray Gnatcatcher In Sierra Madre Occidental Population Forecast

If the recent trend holds, Blue-gray Gnatcatcher in Sierra Madre Occidental is projected to fall about 11% by 2029 — from 1.4 in 2024 to a central estimate of 1.3 (95% range 0.58–2.0). A 5-year backtest shows a typical error of ±29.6%, with 100% of held-out values landing inside the 95% band.

-11%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 →
1.3Projected 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 →
0.58–2.095% 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 →
±29.6%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, Blue-gray Gnatcatcher in Sierra Madre Occidental is projected to fall about 11% by 2029 — from 1.4 in 2024 to a central estimate of 1.3 (95% range 0.58–2.0). A 5-year backtest shows a typical error of ±29.6%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20251.20.521.9
20261.20.541.9
20271.30.552.0
20281.30.562.0
20291.30.582.0

Routes In Sierra Madre Occidental

Routes recording Blue-gray Gnatcatcher 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 →
Emory PassNEW-MEXICO102024
PortalARIZONA72024
SprucedaleARIZONA52023
Vicks PeakNEW-MEXICO42024
BlueARIZONA31989
Tonto Vill.ARIZONA32021
Clay SpringARIZONA32012
Carr MtnARIZONA32024
PrescottARIZONA22015
Mormon LakeARIZONA21968
RedingtonARIZONA22023
Aztec PeakARIZONA11978
Peña BlancaARIZONA11996
WilliamsARIZONA11993
Skull ValleyARIZONA12015
Forest LakesARIZONA12024
PinetopARIZONA12018
Bartlett ResARIZONA12024
Mt. GrahamARIZONA12022
Sunizona 2ARIZONA12014
RuckerARIZONA12000
ReserveNEW-MEXICO12023
MagdalenaNEW-MEXICO12002

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