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

Brown Thrasher Population Trend in Maryland

All statesGeneralists

Brown Thrasher in Maryland has held roughly steady: down 9% on the route-weighted index since 1968.

-9%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 →
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 Brown Thrasher 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 →

No notable trend signals for Brown Thrasher in Maryland. See the full index history below.

Brown Thrasher Population Forecast in Maryland

If the recent trend holds, Brown Thrasher in Maryland is projected to fall about 31% by 2029 — from 4.4 in 2024 to a central estimate of 3.0 (95% range 0.99–5.0). A 5-year backtest shows a typical error of ±40%, with 60% of held-out values landing inside the 95% band.

-31%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 →
3.0Projected 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 →
0.99–5.095% 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 →
±40%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, Brown Thrasher in Maryland is projected to fall about 31% by 2029 — from 4.4 in 2024 to a central estimate of 3.0 (95% range 0.99–5.0). A 5-year backtest shows a typical error of ±40%, with 60% 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 →
20253.11.05.1
20263.01.05.1
20273.01.05.0
20283.01.05.0
20293.00.995.0

Brown Thrasher Survey Routes in Maryland

Routes recording Brown Thrasher 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 →
Emmitsburg1920241966
Earlton1820242014
Pomfret1520241966
Hughesville1420241966
Finzel1020241995
Eklo920181966
Tall Timbers920141966
Grove Neck919961992
Williamsport720241966
La Plata720091966
Green Ridge720241995
Forest Grove720232011
Bald Friar719961992
Ijamsville720241986
Island Creek720241991
Smithsburg520141966
Melitota520241966
Matthews520241966
Madison520241966
St. George'S Island520172015
Walnut520241999
Madonna520222009
Davidsnville520241982
Olney420241966
Harmony420171966

Brown Thrasher Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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