BirdAnalyst
Species · New Mexico · BBS 2025 Release · 1966–2024

Black-crowned Night Heron Population Trend in New Mexico

All statesWetland birds

Black-crowned Night Heron in New Mexico has collapsed: down 82% on the route-weighted index since 1972.

-82%Since 1972TrendPercent 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 →
10Routes 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 →
33YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Black-crowned Night Heron Trends in New MexicoNotable 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 declinecomputed 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 →

Black-crowned Night Heron has collapsed in New Mexico: down 81% on the route-weighted index since 1972.

Black-crowned Night Heron Population Forecast in New Mexico

If the recent trend holds, Black-crowned Night Heron in New Mexico is projected to fall about 72% by 2029 — from 0.09 in 2024 to a central estimate of 0.02 (95% range 0.00–0.18). A 5-year backtest shows a typical error of ±60.8%, with 80% of held-out values landing inside the 95% band.

-72%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 →
0.02Projected 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 →
0.00–0.1895% 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 →
±60.8%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, Black-crowned Night Heron in New Mexico is projected to fall about 72% by 2029 — from 0.09 in 2024 to a central estimate of 0.02 (95% range 0.00–0.18). A 5-year backtest shows a typical error of ±60.8%, with 80% of held-out values landing inside the 95% band.19682029
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 →
20250.030.000.19
20260.030.000.18
20270.030.000.18
20280.030.000.18
20290.020.000.18

Black-crowned Night Heron Survey Routes in New Mexico

Routes recording Black-crowned Night Heron in New Mexico.
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 →
Laborcita 2220242024
Valencia219961968
Stinking Lk.219961996
Laborcita120191992
Mesilla119971992
Hobbs120242006
Angel Fire 2120242009
Maxwell120172017
Gallinas120052005
Variadero120132007

Black-crowned Night Heron Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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