BirdAnalyst
Species · New Hampshire · BBS 2025 Release · 1966–2024

Blue-gray Gnatcatcher Population Trend in New Hampshire

All statesForest birds

Blue-gray Gnatcatcher in New Hampshire has surged: up 141% on the route-weighted index since 1977.

+141%Since 1977TrendPercent 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 →
11Routes 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 →
19YearsYears 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 New HampshireNotable 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 New Hampshire: up 141% on the route-weighted index since 1977.

Blue-gray Gnatcatcher Population Forecast in New Hampshire

If the recent trend holds, Blue-gray Gnatcatcher in New Hampshire is projected to rise about 77% by 2029 — from 0.09 in 2024 to a central estimate of 0.16 (95% range 0.01–0.31). A 5-year backtest shows a typical error of ±38.7%, with 60% of held-out values landing inside the 95% band.

+77%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 →
0.16Projected 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 →
0.01–0.3195% 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 →
±38.7%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 New Hampshire is projected to rise about 77% by 2029 — from 0.09 in 2024 to a central estimate of 0.16 (95% range 0.01–0.31). A 5-year backtest shows a typical error of ±38.7%, with 60% of held-out values landing inside the 95% band.19712029
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 →
20250.150.010.30
20260.150.010.30
20270.160.010.30
20280.160.010.30
20290.160.010.31

Blue-gray Gnatcatcher Survey Routes in New Hampshire

Routes recording Blue-gray Gnatcatcher in New Hampshire.
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 →
Peterborough220191971
Hopkinton220191975
Strafford220221995
Brentwood119961996
Fitzwilliam120242021
Dover120242005
Epsom120192019
East Kingston120142014
Franconia119771977
Milan119801980
Jeffers Ntch120162016

Blue-gray Gnatcatcher Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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