BirdAnalyst
Species · BCR 30 · BBS 2025 Release · 1966–2024

Royal Tern In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastWetland birds

Royal Tern in New England / Mid-Atlantic Coast has fallen sharply: down 54% on the route-weighted index since 1969.

-54%Since 1969TrendPercent 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 RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
28YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 →

Royal Tern has fallen sharply in New England / Mid-Atlantic Coast: down 54% on the route-weighted index since 1969.

Royal Tern In New England / Mid-Atlantic Coast Population Forecast

If the recent trend holds, Royal Tern in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2028, near 0.19 (95% range 0.00–0.64). A 5-year backtest shows a typical error of ±1245.1%, 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 →
0.19Projected 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 →
0.00–0.6495% 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 →
±1245.1%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, Royal Tern in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2028, near 0.19 (95% range 0.00–0.64). A 5-year backtest shows a typical error of ±1245.1%, with 100% of held-out values landing inside the 95% band.19662028
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 →
20240.180.000.63
20250.180.000.63
20260.190.000.63
20270.190.000.64
20280.190.000.64

Routes In New England / Mid-Atlantic Coast

Routes recording Royal Tern in New England / Mid-Atlantic Coast.
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 →
Cape CharlesVIRGINIA112007
Snow HillMARYLAND71968
SinepuxentMARYLAND31973
White StoneVIRGINIA32017
Bethany BchDELAWARE21985
HongaMARYLAND22023
BerlinMARYLAND21996
SharpsVIRGINIA21999
Chincoteag WVIRGINIA22022
Tall TimbersMARYLAND11997
FruitlandMARYLAND11985
NewarkMARYLAND11968
St. George'S IslandMARYLAND12015
Toms RiverNEW-JERSEY11970
QuinbyVIRGINIA12006
GloucesterVIRGINIA12001
Colonial PkyVIRGINIA11998

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