BirdAnalyst
Species · Pennsylvania · BBS 2025 Release · 1966–2024

Bobolink Population Trend in Pennsylvania

All statesGrassland birds

Bobolink in Pennsylvania has declined: down 36% on the route-weighted index since 1968.

-36%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 →
100Routes 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 →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bobolink 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 →

No notable trend signals for Bobolink in Pennsylvania. See the full index history below.

Bobolink Population Forecast in Pennsylvania

If the recent trend holds, Bobolink in Pennsylvania is projected to stay roughly flat through 2029, near 3.4 (95% range 1.5–5.4). A 5-year backtest shows a typical error of ±46.4%, with 100% of held-out values landing inside the 95% band.

+5%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 →
3.4Projected 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 →
1.5–5.495% 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 →
±46.4%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, Bobolink in Pennsylvania is projected to stay roughly flat through 2029, near 3.4 (95% range 1.5–5.4). A 5-year backtest shows a typical error of ±46.4%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20253.51.65.5
20263.51.55.4
20273.51.55.4
20283.41.55.4
20293.41.55.4

Bobolink Survey Routes in Pennsylvania

Routes recording Bobolink 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 →
Arnot5920241969
Little Marsh4720241967
Honesdale2620241972
Starlight 22320242000
Poyntelle2220241969
Greentown1820231969
Rush1420241970
Susquehanna1320241971
Starlight1219991970
Akeley919791966
Sigel820241981
West Grove819921970
Ellenton820241982
Eldred720141973
Brunnerville720041982
Roulette 2720242022
Harmonsburg620231966
Mawr Glen620241966
Austinville620241966
Waller620241971
Brick Tavern619911991
Odin520241973
Bow Bridge520231969
Garrett520241966
Logue420231970

Bobolink Population Trend in Other States

californiacoloradoconnecticutidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonrhode-islandsouth-dakotautahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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