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Species · Maryland · BBS 2025 Release · 1966–2024

Rose-breasted Grosbeak Population Trend in Maryland

All statesGeneralists

Rose-breasted Grosbeak in Maryland has surged: up 818% on the route-weighted index since 1969.

+818%Since 1969TrendPercent 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 →
21Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Rose-breasted Grosbeak 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 →

Rose-breasted Grosbeak has surged in Maryland: up 818% on the route-weighted index since 1969.

Rose-breasted Grosbeak Population Forecast in Maryland

If the recent trend holds, Rose-breasted Grosbeak in Maryland is projected to rise about 16% by 2029 — from 0.45 in 2024 to a central estimate of 0.53 (95% range 0.25–0.81). A 5-year backtest shows a typical error of ±34.6%, with 100% of held-out values landing inside the 95% band.

+16%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 →
0.53Projected 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 →
0.25–0.8195% 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 →
±34.6%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, Rose-breasted Grosbeak in Maryland is projected to rise about 16% by 2029 — from 0.45 in 2024 to a central estimate of 0.53 (95% range 0.25–0.81). A 5-year backtest shows a typical error of ±34.6%, 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 →
20250.500.220.78
20260.510.230.79
20270.510.230.79
20280.520.240.80
20290.530.250.81

Rose-breasted Grosbeak Survey Routes in Maryland

Routes recording Rose-breasted Grosbeak 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 →
Jennings720241995
Finzel720241995
Wolfsville520051988
Accident 2320242021
Smithsburg220051997
Steyer220231996
Accident220151992
Ijamsville220142014
Floyd120241966
Mt Nebo119911975
Vindex120231970
Oldtown120051983
Potomac Park120211981
Bald Friar119951995
Olney120162016
Bachman Mill120071991
Eklo119871969
Upper Xrds119731970
Van Bibber119981998
Green Ridge120241995
Piney Grove120141995

Rose-breasted Grosbeak Population Trend in Other States

arkansasconnecticutgeorgiaillinoisindianaiowakansaskentuckymainemassachusettsmichiganminnesotamissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-dakotatennesseevermontvirginiawest-virginiawisconsinwyoming

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