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Species · Pennsylvania · BBS 2026 Release · 1966–2025

Blue-gray Gnatcatcher Population Trend in Pennsylvania

All statesForest birds

Blue-gray Gnatcatcher in Pennsylvania has surged: up 233% on the route-weighted index since 1968.

+233%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 →
124Routes 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 Blue-gray Gnatcatcher Trends in PennsylvaniaNotable 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 surged in Pennsylvania: up 233% on the route-weighted index since 1968.

Blue-gray Gnatcatcher Population Forecast in Pennsylvania

If the recent trend holds, Blue-gray Gnatcatcher in Pennsylvania is projected to rise about 24% by 2030 — from 1.3 in 2025 to a central estimate of 1.6 (95% range 0.86–2.2). A 5-year backtest shows a typical error of ±41.5%, with 80% of held-out values landing inside the 95% band.

+24%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 →
1.6Projected 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 →
0.86–2.295% 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 →
±41.5%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, Blue-gray Gnatcatcher in Pennsylvania is projected to rise about 24% by 2030 — from 1.3 in 2025 to a central estimate of 1.6 (95% range 0.86–2.2). A 5-year backtest shows a typical error of ±41.5%, 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 →
20261.50.812.2
20271.50.822.2
20281.50.842.2
20291.50.852.2
20301.60.862.2

Blue-gray Gnatcatcher Survey Routes in Pennsylvania

Routes recording Blue-gray Gnatcatcher in Pennsylvania.
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 →
Ramsey1020251981
Ryde1020051978
Stoneybreak820251992
Pine Gr Mill720251971
Mt Gretna 2720172014
Tussey Mtn.620251993
Sardis519741970
N Washington420251967
Eldred420151987
Beaver420251978
Naginey420251976
Hometown420251973
Doe Run420251971
Drehersville 2420252000
Berwick420251985
Wild Creek420251988
Honesdale320251975
Clear Spring320251966
Scheafferstn320011999
Laurel Hill320251978
Chatham320252000
Broad Mtn.320251993
Espyville220171994
Ferris Crnrs220241975
Lynch220142003

Blue-gray Gnatcatcher Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonrhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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