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

Summer Tanager Population Trend in Maryland

All statesGeneralists

Summer Tanager in Maryland has surged: up 219% on the route-weighted index since 1968.

+219%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 →
45Routes 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 Summer Tanager 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 →

Summer Tanager has surged in Maryland: up 219% on the route-weighted index since 1968.

Summer Tanager Population Forecast in Maryland

If the recent trend holds, Summer Tanager in Maryland is projected to fall about 27% by 2029 — from 2.4 in 2024 to a central estimate of 1.7 (95% range 0.95–2.5). A 5-year backtest shows a typical error of ±45.3%, with 0% of held-out values landing inside the 95% band.

-27%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 →
1.7Projected 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 →
0.95–2.595% 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 →
±45.3%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, Summer Tanager in Maryland is projected to fall about 27% by 2029 — from 2.4 in 2024 to a central estimate of 1.7 (95% range 0.95–2.5). A 5-year backtest shows a typical error of ±45.3%, with 0% 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 →
20251.60.862.4
20261.70.882.4
20271.70.912.4
20281.70.932.5
20291.70.952.5

Summer Tanager Survey Routes in Maryland

Routes recording Summer Tanager 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 →
Cokesbury2620241966
Furnace Town1120242015
Island Creek1020241991
Berlin720241980
Tall Timbers720141966
Forest Grove720232011
St. George'S Island720172015
Pomonkey620241966
Madison620241968
Walnut520242000
Honga520241966
Newark520241966
Pomfret420241968
Indiantown420141977
Nottingham420242006
Pt Republic219891968
Harmony220171968
Matthews220241968
Golden Hill220241966
Fruitland219981967
Sinepuxent219741971
Snow Hill219761967
Davidsnville220241982
Oldtown119891984
Grove Neck119961996

Summer Tanager Population Trend in Other States

alabamaarizonaarkansascaliforniadelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamississippimissourinebraskanevadanew-jerseynew-mexiconorth-carolinaohiooklahomapennsylvaniasouth-carolinatennesseetexasutahvirginiawest-virginiawisconsin

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