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

Little Blue Heron Population Trend in Maryland

All statesWetland birds

Little Blue Heron in Maryland has edged down: down 19% on the route-weighted index since 1970.

-19%Since 1970TrendPercent 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 →
17Routes 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 →
36YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Little Blue Heron 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 Little Blue Heron in Maryland. See the full index history below.

Little Blue Heron Population Forecast in Maryland

If the recent trend holds, Little Blue Heron in Maryland is projected to stay roughly flat through 2028, near 0.01 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±33.6%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.01Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1595% 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 →
±33.6%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, Little Blue Heron in Maryland is projected to stay roughly flat through 2028, near 0.01 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±33.6%, with 100% of held-out values landing inside the 95% band.19672028
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 →
20240.010.000.16
20250.010.000.16
20260.010.000.16
20270.010.000.15
20280.010.000.15

Little Blue Heron Survey Routes in Maryland

Routes recording Little Blue Heron 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 →
Sinepuxent419751973
Walnut420052005
Northeast319721972
Elkton220181976
Vienna219871987
Severna Park219911991
Millington120002000
Grove Neck119921992
Easton120122012
Honga120001968
Madison120141977
Cokesbury120211994
Newark120231967
Snow Hill119731973
Berlin119871987
Indiantown120101979
Tall Timbers119751972

Little Blue Heron Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaillinoiskansaskentuckylouisianamassachusettsmississippimissourinew-jerseynew-yorknorth-carolinanorth-dakotaoklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvirginia

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