BirdAnalyst
Species · BCR 31 · BBS 2025 Release · 1966–2024

Double-crested Cormorant In Peninsular Florida

All regionsPeninsular FloridaWetland birds

Double-crested Cormorant in Peninsular Florida has collapsed: down 95% on the route-weighted index since 1968.

-95%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 →
70Routes 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 →
58YearsYears 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 →

Double-crested Cormorant has collapsed in Peninsular Florida: down 95% on the route-weighted index since 1968.

Double-crested Cormorant In Peninsular Florida Population Forecast

If the recent trend holds, Double-crested Cormorant in Peninsular Florida is projected to fall about 100% by 2029 — from 0.29 in 2024 to a central estimate of 0.00 (95% range 0.00–4.1). A 5-year backtest shows a typical error of ±99.7%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–4.195% 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 →
±99.7%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, Double-crested Cormorant in Peninsular Florida is projected to fall about 100% by 2029 — from 0.29 in 2024 to a central estimate of 0.00 (95% range 0.00–4.1). A 5-year backtest shows a typical error of ±99.7%, 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 →
20250.000.004.1
20260.000.004.1
20270.000.004.1
20280.000.004.1
20290.000.004.1

Routes In Peninsular Florida

Routes recording Double-crested Cormorant in Peninsular Florida.
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 →
Plantation KFLORIDA802004
ShawanoFLORIDA702002
Key WestFLORIDA291987
Sugarloaf KeyFLORIDA272004
Merritt IslFLORIDA132011
Merritt Island 2FLORIDA132014
Ridge HarborFLORIDA112015
ScottsmoorFLORIDA72024
AndytownFLORIDA71998
St AugustineFLORIDA62014
Pennywash CrFLORIDA62017
Key LargoFLORIDA61991
Sandy 2FLORIDA52016
Shawano 2FLORIDA52011
Dale MabryFLORIDA41986
Myakka HeadFLORIDA42011
TamiamiFLORIDA41971
Lake BuffumFLORIDA42014
SebastianFLORIDA31991
Citrus ParkFLORIDA32017
CrewsvilleFLORIDA32016
Vero BeachFLORIDA32022
MabelFLORIDA22007
ChildsFLORIDA22016
Sunniland GrFLORIDA22001

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