BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Black-legged Kittiwake

LaridaeWetland birdsRissa tridactyla

Black-legged Kittiwake has surged: up 572% on the route-weighted index since 1982.

+572%Since 1982TrendPercent 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 →
16RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
41Years 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 Black-legged Kittiwake

The Black-legged Kittiwake (Rissa tridactyla) is a North American member of the Gulls, Terns & Skimmers (Laridae). In this analysis it is grouped with the wetland birds.

Size
8.5–31.5 in long (22–80 cm) — a long-winged waterbird (typical for the family)
Habitat
Marshes, ponds, lakeshores and other freshwater wetlands.
Diet
Aquatic invertebrates, small fish, frogs and plant matter.
Range
Recorded on 16 Breeding Bird Survey routes across 2 states, most concentrated in the Northern Pacific Rainforest.
Family
Laridae · Wetland birds

Notable Black-legged Kittiwake 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 Black-legged Kittiwake. See the full index history below.

Black-legged Kittiwake Population Forecast

If the recent trend holds, Black-legged Kittiwake is projected to rise about 23% by 2029 — from 0.12 in 2024 to a central estimate of 0.15 (95% range 0.00–0.41). A 5-year backtest shows a typical error of ±483.4%, with 100% of held-out values landing inside the 95% band.

+23%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 →
0.15Projected 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 →
0.00–0.4195% 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 →
±483.4%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-legged Kittiwake is projected to rise about 23% by 2029 — from 0.12 in 2024 to a central estimate of 0.15 (95% range 0.00–0.41). A 5-year backtest shows a typical error of ±483.4%, with 100% of held-out values landing inside the 95% band.19702029
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 →
20250.140.000.40
20260.140.000.40
20270.140.000.41
20280.150.000.41
20290.150.000.41

Where the Black-legged Kittiwake Is Detected

BBS routes recording Black-legged Kittiwake, sized by most recent count.

Black-legged Kittiwake Population Trend by State

Black-legged Kittiwake 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 →
Alaska+21%198315
Washingtoninsufficient datan/a1

Black-legged Kittiwake Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Black-legged Kittiwake 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 →
BCR 249×19906
Northern Pacific Rainforest-81%19847

Black-legged Kittiwake Conservation Status

Our route-weighted index shows it up about 572% since 1982.

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