BirdAnalyst
Species · BCR 37 · BBS 2025 Release · 1966–2024

Double-crested Cormorant In Gulf Coastal Prairie

All regionsGulf Coastal PrairieWetland birds

Double-crested Cormorant in Gulf Coastal Prairie has surged: up 101% on the route-weighted index since 1975.

+101%Since 1975TrendPercent 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 →
26Routes 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 →
43YearsYears 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 increasecomputed 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 →

Double-crested Cormorant has surged in Gulf Coastal Prairie: up 101% on the route-weighted index since 1975.

Forecast

If the recent trend holds, Double-crested Cormorant in Gulf Coastal Prairie is projected to stay roughly flat through 2029, near 0.86 (95% range 0.00–2.7). A 5-year backtest shows a typical error of ±716.5%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.86Projected 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 →
0.00–2.795% 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 →
±716.5%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, Double-crested Cormorant in Gulf Coastal Prairie is projected to stay roughly flat through 2029, near 0.86 (95% range 0.00–2.7). A 5-year backtest shows a typical error of ±716.5%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.870.002.7
20260.870.002.7
20270.870.002.7
20280.870.002.7
20290.860.002.7

Routes In Gulf Coastal Prairie

Routes recording Double-crested Cormorant in Gulf Coastal Prairie.
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 →
CreoleLOUISIANA201987
KatyTEXAS201985
Gran ChenierLOUISIANA141982
BaysideTEXAS102010
EstherLOUISIANA92014
PetronilaTEXAS72016
Lag AtascosaTEXAS61992
ChinquapinTEXAS52021
Sabine Nwr 2LOUISIANA32017
Sabine NwrLOUISIANA22003
IndianolaTEXAS22007
StowellTEXAS21994
Padre Island PaisTEXAS22015
JuniorLOUISIANA11991
HackberryLOUISIANA11971
GlencoeLOUISIANA11998
KaplanLOUISIANA12019
Ltl ChenierLOUISIANA12024
WoodlawnLOUISIANA12018
Forked Island 2LOUISIANA12010
DanburyTEXAS12023
Rock IslandTEXAS12019
Loyola BeachTEXAS11998
Oyster LakeTEXAS12023
Loyola Beach 2TEXAS12016

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