Species · BBS 2025 Release · 1966–2024

Black-crowned Night Heron

ArdeidaeWetland birdsNycticorax nycticorax

Black-crowned Night Heron has fallen sharply: down 57% on the route-weighted index since 1968.

About the Black-crowned Night Heron

The Black-crowned Night Heron (Nycticorax nycticorax) 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 816 Breeding Bird Survey routes across 48 states, most concentrated in the Great Basin.
Family
Ardeidae · Wetland birds

Notable Black-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 →

Black-crowned Night Heron has fallen sharply in surveyed states: down 57% on the route-weighted index since 1968.

Black-crowned Night Heron Population Forecast

If the recent trend holds, Black-crowned Night Heron is projected to stay roughly flat through 2029, near 0.08 (95% range 0.00–0.16). A 5-year backtest shows a typical error of ±72.4%, with 100% of held-out values landing inside the 95% band.

If the recent trend holds, Black-crowned Night Heron is projected to stay roughly flat through 2029, near 0.08 (95% range 0.00–0.16). A 5-year backtest shows a typical error of ±72.4%, 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 →
20250.090.010.17
20260.090.010.17
20270.090.000.17
20280.080.000.16
20290.080.000.16

Where the Black-crowned Night Heron Is Detected

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

Black-crowned Night Heron Population Trend by State

Black-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+194%197217
Arizona-60%19858
Arkansasinsufficient datan/a3
California+152%197180
Colorado-94%197019
Connecticut-5%19806
Delaware+34%19728
Florida+4%196963
Georgia-96%196922
Idaho-80%19749
Illinois-34%196820
Indiana-40%198310
Iowainsufficient datan/a7
Kansas-90%196920
Kentuckyinsufficient datan/a7
Louisiana+72%197049
Maine-66%19766
Maryland-75%197514
Massachusetts-39%19699
Michiganinsufficient datan/a10
Minnesota-95%197025
Mississippiinsufficient datan/a11
Missouri-74%19707
Montanainsufficient datan/a9
Nebraska-48%197413
Nevada-90%198218
New Hampshireinsufficient datan/a6
New Jersey-45%197113
New Mexico-82%197210
New York-58%196816
North Carolina-51%198410
North Dakota+11%196930
Ohio-77%19709
Oklahoma-67%196917
Oregon-87%197320
Pennsylvania-46%197024
Rhode Island-8%19703
South Carolina-66%19716
South Dakota-87%196920
Tennessee-21%19686
Texas+447%197077
Utah-50%197315
Vermontinsufficient datan/a1
Virginia-50%19887
Washington-95%197517
West Virginiainsufficient datan/a2
Wisconsin-21%196824
Wyoming-93%197913

Black-crowned Night Heron Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Black-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 →
Northern Pacific Rainforest-6%197511
Great Basin+80%197176
Northern Rockies-58%197918
Prairie Potholes-73%196960
Lower Great Lakes / St. Lawrence Plain-47%197115
Atlantic Northern Forest-33%19769
Southern Rockies / Colorado Plateau-93%197026
Badlands and Prairies-78%196914
Shortgrass Prairie+213%197832
Central Mixed Grass Prairie-97%196939
Oaks and Prairies-59%196921
Eastern Tallgrass Prairie-60%196835
Prairie Hardwood Transition-61%196846
Central Hardwoods+239%197020
West Gulf Coastal Plain / Ouachitas-36%197517
Mississippi Alluvial Valley+94%197032
Southeastern Coastal Plain-80%196868
Appalachian Mountains-72%196926
Piedmont-72%197417
New England / Mid-Atlantic Coast-74%196861
Peninsular Florida+15%196948
Coastal California+119%197152
Sonoran and Mojave Deserts-42%197612
Chihuahuan Desert-7%19956
Gulf Coastal Prairie+140%197037

Black-crowned Night Heron Conservation Status

Our route-weighted index shows it down about 57% 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.