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Species · Maryland · BBS 2026 Release · 1966–2025

Blue-gray Gnatcatcher Population Trend in Maryland

All statesForest birds

Blue-gray Gnatcatcher in Maryland has surged: up 708% on the route-weighted index since 1968.

+708%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 →
76Routes 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 MarylandNotable 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 Maryland: up 708% on the route-weighted index since 1968.

Blue-gray Gnatcatcher Population Forecast in Maryland

If the recent trend holds, Blue-gray Gnatcatcher in Maryland is projected to fall about 24% by 2030 — from 12 in 2025 to a central estimate of 9.2 (95% range 6.6–12). A 5-year backtest shows a typical error of ±25.6%, with 20% 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 →
9.2Projected 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 →
6.6–1295% 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 →
±25.6%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 Maryland is projected to fall about 24% by 2030 — from 12 in 2025 to a central estimate of 9.2 (95% range 6.6–12). A 5-year backtest shows a typical error of ±25.6%, with 20% 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 →
20268.66.011
20278.76.111
20288.96.312
20299.06.412
20309.26.612

Blue-gray Gnatcatcher Survey Routes in Maryland

Routes recording Blue-gray Gnatcatcher in Maryland.
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 →
Pomonkey5520251966
Cokesbury4820251966
Furnace Town4220252015
Island Creek3520251991
Forest Grove2720232011
La Plata2620091966
Jessup2620252013
Honga2520251966
Emmitsburg2220251967
Madison2220251969
Olney2120251966
Oldtown1920251970
Ijamsville1920251986
Earlton1720242014
Pomfret1620241966
Williamsport1520251973
Wheaton1520251990
Berlin1520251980
Madonna1320222009
Tall Timbers1220141966
Pr Frederick1120251991
Smithsburg1020141966
Pt Republic1019891966
Green Ridge920251995
Nottingham920252005

Blue-gray Gnatcatcher Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemassachusettsmichiganminnesotamississippimissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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