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

Purple Martin Population Trend in Maryland

All statesAerial insectivores

Purple Martin in Maryland has surged: up 79% on the route-weighted index since 1968.

+79%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 →
71Routes 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 Purple Martin 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 →

Purple Martin has surged in Maryland: up 79% on the route-weighted index since 1968.

Purple Martin Population Forecast in Maryland

If the recent trend holds, Purple Martin in Maryland is projected to stay roughly flat through 2029, near 12 (95% range 9.7–15). A 5-year backtest shows a typical error of ±9.1%, with 100% of held-out values landing inside the 95% band.

+0%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 →
12Projected 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 →
9.7–1595% 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 →
±9.1%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, Purple Martin in Maryland is projected to stay roughly flat through 2029, near 12 (95% range 9.7–15). A 5-year backtest shows a typical error of ±9.1%, 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 →
2025129.314
2026129.414
2027129.514
2028129.614
2029129.715

Purple Martin Survey Routes in Maryland

Routes recording Purple Martin 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 →
Cokesbury10220241966
Madison7220241966
Harmony6820171966
Honga5920241966
Matthews5620241966
Indiantown3220141977
Forest Grove3020232011
Broomes Isl2519961966
Newark2520241967
Melitota2420241966
St. George'S Island2320172015
Piney Neck2220241966
Vienna2120241966
Madonna1920222009
Ijamsville1820241992
Easton1720211969
Fruitland1519981966
Grove Neck1419961992
Nottingham1420242005
Walnut1320241999
Pt Republic1219891967
Williamsport1120241966
Silver Spg1119891966
Tall Timbers1120141966
Emmitsburg1020241967

Purple Martin Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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