BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Yellow-crowned Night Heron

ArdeidaeWetland birdsNyctanassa violacea

Yellow-crowned Night Heron has edged up: up 20% on the route-weighted index since 1968.

+20%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 →
499RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Yellow-crowned Night Heron

The Yellow-crowned Night Heron (Nyctanassa violacea) is a North American member of the Herons, Egrets & Bitterns (Ardeidae). In this analysis it is grouped with the wetland birds.

Size
12–51 in long (30–130 cm) — a long-legged wader (typical for the family)
Habitat
Marshes, ponds, lakeshores and other freshwater wetlands.
Diet
Aquatic invertebrates, small fish, frogs and plant matter.
Range
Recorded on 499 Breeding Bird Survey routes across 25 states, most concentrated in the Southeastern Coastal Plain.
Family
Ardeidae · Wetland birds

Notable Yellow-crowned Night Heron TrendsNotable 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 Yellow-crowned Night Heron. See the full index history below.

Yellow-crowned Night Heron Population Forecast

If the recent trend holds, Yellow-crowned Night Heron is projected to stay roughly flat through 2029, near 0.08 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±95.7%, with 100% of held-out values landing inside the 95% band.

-4%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 →
0.08Projected 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 →
0.00–0.1595% 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 →
±95.7%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, Yellow-crowned Night Heron is projected to stay roughly flat through 2029, near 0.08 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±95.7%, 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 →
20250.080.000.15
20260.080.000.15
20270.080.000.15
20280.080.000.15
20290.080.000.15

Where the Yellow-crowned Night Heron Is Detected

BBS routes recording Yellow-crowned Night Heron, sized by most recent count.

Yellow-crowned Night Heron Population Trend by State

Yellow-crowned Night Heron population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alabama+6%196854
Arkansas-40%196924
Connecticutinsufficient datan/a2
Delawareinsufficient datan/a2
Florida-89%196865
Georgia-57%197534
Illinois-69%19746
Indianainsufficient datan/a2
Kansas-46%19738
Kentucky+33%197410
Louisiana+124%196978
Marylandinsufficient datan/a7
Mississippi-82%197031
Missouri-64%198310
New Jersey-29%19833
New Yorkinsufficient datan/a2
North Carolina-52%197410
Ohioinsufficient datan/a1
Oklahoma-54%196923
Pennsylvaniainsufficient datan/a2
South Carolina-10%197511
Tennessee-34%197315
Texas+14%196989
Virginia-64%19819
West Virginiainsufficient datan/a1

Yellow-crowned Night Heron Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Yellow-crowned Night Heron population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Central Mixed Grass Prairie-77%196919
Oaks and Prairies-15%196948
Central Hardwoods-50%197124
West Gulf Coastal Plain / Ouachitas-52%196972
Mississippi Alluvial Valley+149%196944
Southeastern Coastal Plain-2%1968148
Appalachian Mountains-78%196921
New England / Mid-Atlantic Coast+38%197515
Peninsular Florida-90%196944
Gulf Coastal Prairie+313%196936

Yellow-crowned Night Heron Conservation Status

Our route-weighted index shows it up about 20% since 1968.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.