BirdAnalyst
Species · BCR 10 · BBS 2025 Release · 1966–2024

Double-crested Cormorant In Northern Rockies

All regionsNorthern RockiesWetland birds

Double-crested Cormorant in Northern Rockies has held roughly steady: down 5% on the route-weighted index since 1983.

-5%Since 1983TrendPercent 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 →
44Routes 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 →

No notable trend signals for Double-crested Cormorant in Northern Rockies. See the full index history below.

Forecast

If the recent trend holds, Double-crested Cormorant in Northern Rockies is projected to rise about 213% by 2029 — from 0.14 in 2024 to a central estimate of 0.45 (95% range 0.01–0.88). A 5-year backtest shows a typical error of ±169.4%, with 100% of held-out values landing inside the 95% band.

+213%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 →
0.45Projected 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 →
0.01–0.8895% 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 →
±169.4%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, Double-crested Cormorant in Northern Rockies is projected to rise about 213% by 2029 — from 0.14 in 2024 to a central estimate of 0.45 (95% range 0.01–0.88). A 5-year backtest shows a typical error of ±169.4%, with 100% of held-out values landing inside the 95% band.19762029
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 →
20250.420.000.86
20260.430.000.86
20270.430.000.87
20280.440.010.87
20290.450.010.88

Routes In Northern Rockies

Routes recording Double-crested Cormorant in Northern Rockies.
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 →
Neponset ResUTAH552018
Saleratus CrUTAH112018
FontenelleWYOMING102024
AugustaMONTANA82022
Rock RiverWYOMING71999
HarmonyWYOMING62014
MooseWYOMING52014
Hebgen LakeMONTANA42023
Elk HornWYOMING42000
ArleeMONTANA31988
Red RockMONTANA32023
Colter BayWYOMING31996
NaplesIDAHO22024
Crane CreekIDAHO22000
FeathervilleIDAHO22004
BoulderMONTANA22003
BeaverheadMONTANA22024
East Glacier ParkMONTANA22018
WoodruffUTAH22022
CusickWASHINGTON22024
CodyWYOMING21997
OttoWYOMING22015
EtheteWYOMING22021
SweetwaterWYOMING21997
CabartonIDAHO12010

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